Four teenagers from the Southway comprehensive school in Plymouth died last March after an expedition organised by the St Alban’s Centre in Lyme Regis went disastrously wrong.

The Hampshire court has been told that the instructors in charge of the expedition across Lyme Bay had only the most basic qualifications.

The deaths have focused nationwide attention on activity and adventure organisations, and the fear that many operate with inadequately trained staff.

Peter Kite, former managing director of the company which owned the St Alban’s Centre, Active Learning and Leisure Limited, and Joseph Stoddart, manager of the centre, each deny four charges of manslaughter.

The trial has already heard evidence from the survivors of the tragedy, including the two instructors, who had only passed the British Canoe Union’s most basic proficiency test. Neither was qualified to lead the group of eight sixth-formers and a teacher, according to a senior BCU instructor.

The pupils had practised only in a swimming pool before tackling the waters of the English Channel, and carried no distress flares. No one at the St Alban’s Centre had checked the weather forecast, the court heard.

Although the sea looked calm from the shore, the party quickly ran into difficulties, and as waves crashed over the children’s heads, all the canoes capsized. Pupils Claire Langley, Rachel Walker and Simon Dunne, all aged 16, and 17-year-old Dean Sayer died.

The survivors read emotional statements to the court describing their friends’ last hours as the party clung to the upturned hull of a single canoe.

This week, the court heard that the canoeing centre took more than two hours to notify the coastguard after the pupils failed to arrive safely at Charmouth, their intended destination. A lifeboat was not launched until 4.25pm, even though the group had been due back by midday. The trial is now in its second week, with the prosecution case continuing.