A new play by Vera Drake director Mike Leigh has sold out - even though its subject matter and even its real name are closely guarded secrets.

The reputation of the OSCAR-nominated film-maker has ensured the sale of 16,000 tickets at London's National Theatre for next month's (SEP05) stage run - despite a clandestine cloak surrounding the simply titled production 'A New Play By Mike Leigh.'

Leigh and his eight cast members began rehearsing four months ago at a secret location in the British capital - and the 62-year-old famously encourages his actors to improvise their parts.

A National Theatre spokesperson says, "We are not keeping anything back, it is just that we know nothing. We are as much in the dark as everybody else.

"Details of the plot are known only to those directly involved in the rehearsal process."