The crunch of warm sand under foot, the salty breeze, the cry of seagulls; ice cream, buckets and spades, rock pools and the smell of fish and chips: what could be better than a day at the beach? But our use of the coast for pleasure is relatively recent.

Humans are land animals, and the edge of the land is the boundary of our natural habitat, which may partly explain our primitive fascination with the coast.

Britain has 15,000km of coastline and, wherever you are in the British Isles, you are never more than 200km from the sea. Nonetheless, it was only the development of cheap, mass transport in the 19th century - coupled with social improvements that gave workers paid holidays - that put the seaside within the reach of ordinary people. Before this, most people would probably never even have seen the sea.

Steaming ahead We use the sea as a source of food, a means of reaching other countries, and as a dustbin. The earliest coastal settlements were fishing villages, followed by the ports that grew up to serve the sailors, shipbuilders, traders and others who depended on the sea. The castles that command headlands from Bamburgh, on the Northumbrian coast, to Tintagel, in Cornwall, were our defence against invaders. So were the Martello towers, built to deter Napoleon’s warships, and the concrete slabs shoved among the dunes around 60 years ago to stop enemy tanks.

Until the start of the last century, however, only the very rich could afford to go to the coast for fun. Even for them the journey, by coach and sailing ship, would have been slow and uncomfortable. Still, the seaside was gaining an edge over the inland spas favoured by the well-to-do in the 18th century. Brighton was fashionable, as were Scarborough and Margate.

When steamships emerged from the Glasgow shipyards in 1812, the seaside became more accessible. Soon steam packets were plying all round the coast, but passengers had to be rowed ashore in small boats as the ships needed to moor in deep water. This was inconvenient, so piers were built stretching out into the sea on to which passengers could disembark. From these humble origins grew one of the glories of the British seaside, the pleasure pier.

But it was railways, from the 1830s on, that brought large numbers of people to the beach. Railways were first used to transport industrial materials around the country, but their owners soon realised that money could be made from holidaymakers, and lines were built to coastal spots. Fishing families took in paying guests; restaurants, hotels and churches were built; piers became places of amusement and the seaside we know today began to develop.

THE AWAY-DAY IS BORN

This was all very well if you could afford it and had the time. Until the middle of the last century most working people had only three days’ holiday a year (the “holy days” of Christmas, Easter and Whitsun), apart from Sundays. By the 1860s, Saturday afternoons had been added. From then on, the idea that people were entitled to paid holidays gained acceptance.

Railway companies responded with one of their most brilliant innovations:

“excursion trains”, which could carry hundreds of people on cheap-day return trips.

By the 1880s, resorts around Britain, from Bournemouth on the south coast to Rothesay in the Firth of Clyde, and from the Cornish Riviera to Tynemouth, were building promenades and ornamental gardens, and trying to provide enough accommodation and entertainment for visitors. The population of seaside resorts could more than double for a few weeks in summer. Entire neighbourhoods from the industrial and inner-city heartlands would decamp en masse only to meet at the beach.

The Victorians liked to buy souvenirs - perhaps a china cruet or a wooden letter rack - while penny-in-the-slot machines on the piers offered peeks at “What the Butler Saw” or the wonders of the world.

Resorts vied with each other to lay on the best, most daring amusements. The great seaside variety theatres, such as Brighton’s Palace on the Pier, were as famous as the London Palladium.

LIFE ON THE EDGE

The seashore teems with life:

* Mermaid’s purses are the pouch-like egg sacs of dogfish and rays; papery, bubble-like clusters are whelk’s eggs.

* A sandy beach can hide shellfish buried under the sand - tallins, cockles and razor shells, all bivalves. These feed and breathe by running twin pipes up to the surface of the sand to suck in water. They extract the oxygen and any nutritious particles, and blow the waste back out.

* You can detect shellfish by the holes they leave in the sand, but you have to dig very quickly to find the razor shell, which can pull itself down half a metre in a few seconds.

* Where the sand is wet, it may be covered with wormcasts, made of mud and sand left by the lugworm as it digs a U-shaped burrow under the sand.

* Rock pools may contain red anemones. These look like exotic flowers but are really animals that shoot their prey with poisonous injections and grab them with their tentacles.

* Other rock pool inhabitants include green shore crabs, hermit crabs (which have soft bodies and need to live in the empty shells of other creatures), prickly urchins, snails, starfish, sponges, and forests of different seaweed.

* Limpets and urchins are herbivores. They extract plankton from seawater, which they filter through their shells.

* The only British shore crab that really bites is the velvet swimming crab, which lives around the coasts of Devon and Cornwall.

* Starfish are voracious carnivores. Once they have wrapped themselves around a mussel or an oyster, they pull hard with their tentacle-coated legs to prise open the shell. Starfish eat through their stomachs. Once they pull their victim’s shell open, they can push their stomach inside.

* The commonest sea birds are the omnivorous herring gulls, with their grey backs and pinkish legs. The biggest gulls are the black backs. The little birds found in crowds along the water’s edge are turnstones, looking for shellfish.

LIFE ON THE EDGE

* Tides are caused by gravity - the Earth’s, the Moon’s and the Sun’s all pulling together. The biggest tides - those that come up highest and go down lowest - are spring tides. These occur twice each month, when the Earth, Sun and Moon are in alignment, and the gravity of the Sun and Moon combines to pull in the same direction. The biggest spring tides of all occur at the spring (around March 20) and autumn (around September 22) equinoxes.

* The smallest tides - when there is much less difference between high and low tide - are neap tides, which also occur twice every month, when the Sun and Moon pull at right angles to each other.

* Most places round Britain have two high tides every day, but Portsmouth has four.

* Currents are movements of water and waves are movements of energy through water. When you watch a wave travelling across the sea, the water is not moving forwards but doing a sort of loop-the-loop.

* Although waves appear to be unpredictable, there is a formula that states that the height of a wave from trough to crest cannot exceed 0.14 of the distance between successive crests without the wave collapsing on itself. This is what causes waves to have “whitecaps”.

* When waves hit shallow coastal water, the lower part of the wave is slowed down by friction with the seabed, while the top keeps travelling at speed, which explains why waves break on the seashore.

* Waves travel across the surface: on a stormy day, the sea may be quite calm underneath.

* Waves are caused by the wind. The strength of waves depends on the strength, duration and “fetch” of the wind - the distance that it has travelled across the sea. The bigger the fetch, the bigger the waves - which is why the best surf is found at the edges of big oceans, such as the Pacific.

Naughty but ‘ice

* The golden age of the British seaside lasted for 100 years or so. It ended when jet aircraft put Mediterranean beaches within the reach of package holidaymakers.

* By the 1930s, racks of naughty postcards had become a seaside feature. They were elevated to a kitsch art form by painter Donald McGill. With mild jokes about hen-pecked husbands and saucy young couples, they sold by the millions.

* After the advent of refrigeration early this century, ice cream became a seaside favourite. It was often made by Italians who brought their recipes with them from Italy.

Piers of the realm

* One of the first piers at Ryde, on the Isle of Wight, was begun in 1813. By 1880 it was more than half-a-mile long, with both a tramway and a railway line (still operational) running along it.

* Brighton’s Chain Pier, completed in 1823, was hailed as a triumph of engineering. It looked like a suspension bridge, with chains secured to a three-ton iron plate. It was badly damaged by fire 10 years later and finally destroyed during a hurricane in 1896.

* Piers sprouted all around the coast: 89 of them were built between 1814 and 1910, from Weston-super-Mare to Bognor, from Rhyl to Cleethorpes, and from Southend to Skegness.

* All the best diversions a resort had to offer were found on the pier, such as fortune-tellers, Punch-and-Judy shows, slot machines and stunt divers.

What a waste

The effluence that is flushed down our toilets goes into the sea. The good news is that in Britain 96 per cent of us are connected to the main sewerage system and nearly all of this sewage is biochemically purified before reaching the sea.

Nevertheless, sea water is often found to contain a variety ofbacteria that can make people ill and harm sea creatures and plants.

The EU Blue Flag scheme and the UK Seaside Award programme inform people about the quality of seawater and highlight the cleanest beaches. For maps of Blue Flag and Seaside Award beaches, call the Tidy Britain Group on 01603 766076.