Record numbers of Britons who are suffering from terminal illnesses are queueing up for assisted suicide at the controversial Swiss clinic Dignitas, the Observer can reveal.

Almost 800 have taken the first step to taking their lives by becoming members of Dignitas, and 34 men and women, who feel their suffering has become unbearable, are ready to travel to Zurich and take a lethal drug overdose.

The tenfold increase in the number of Britons who have joined Dignitas since 2002 will raise questions about the law that bans assisted suicide in Britain.