As we are ushered into Richmond’s Georgian Theatre Royal, dozens of candles twinkle. Many are on chandeliers. They are - powered by electricity but are astonishingly effective.The look is magical and mysterious.

The theatre in this North Yorkshire market town was built in 1788 and is the oldest working theatre in its original form in the UK. It was closed in 1830, then used as a warehouse and auction room. It lay neglected until 1963 when it was re-opened and has remained largely unaltered until major restoration last year.

The place is small enough to retain the charm of a model theatre. Our guide, Jim Russell, calls it a “living museum”, but is too alive to be called such. It is a living piece of history. At any moment you expect someone to walk on stage to perform.

For our benefit, the theatre is in “museum mode” which means that the original wooden benches have been extended over the gangways. The Georgians were used to clambering over the seats. Back then, more than 400 eager, sweaty citizens were allowed into the auditorium, but now the capacity is a much safer 212.

Standing on the stage, you can see the tonsils of everyone on the front rowI and the second and third. You could just about fit a primary classroom into the stalls. Despite this lack of space, professional actors love working here. A Welsh ballet company visits regularly. This is hard to credit when the stage is about the size of the average front room.

There is much of interest in an exhibition area behind the stage. A Georgian theatrical thunder machine to play with, costumes and wigs to try on. Something certainly not to be played with is the oldest complete collection of painted scenery in the UK. There are many excellent story boards, ancient play bills and lots of fascinating archive material.

We are taken into the tiny dressing rooms. One still has a fireplace - a reminder of the days when actors lived in the dressing rooms because they were branded rogues and vagabonds and couldn’t get lodgings in town.

The restoration work has been fastidious and sympathetic, as befits a Grade I listed building. A worn hand rail has been left untouched because it shows samples of paint from three centuries. In the new wing. a huge section of wall has been deliberately left untouched. Here and there are red bricks beneath local stone, crumbling cement mixes from the early 20th century and smooth lime from the Georgian era.

A magnificent new wing makes the theatre look much more Georgian from the outside. It did resemble a barn until the recent work. Indeed, confused visitors would walk past it and have to ask locals for directions.

Theatre tours with guides with a wealth of lively anecdotes for every nook and cranny last 50 minutes and cost pound;1 per head. The theatre’s new manager Vaughn Curtis welcomes educational visits - sessions can be tailored to suit.Georgian Theatre Royal. Tel: 01748 823710; www.georgianheatreroyal.co.uk