Leading playwright Sir Alan Ayckbourn and children from Tower Bridge Primary School have taken part in the Unicorn Theatre groundbreaking ceremony .
Mayor of London Ken Livingstone said: "The Unicorn Theatre is a wonderful project and I am pleased to have been able to help, through the London Development Agency, towards raising the money required to develop it as a world-class theatre for children right in the heart of London.
The project will house a 350 seat auditorium, a 120 seat studio theatre, rehearsal space, a caf√© and exhibition space. The architect is Keith Williams.
Among those at the ceremony were patrons Sir John Mortimer and Jeremy Paxman. Sir John's actress daughter Emily Mortimer started the digging surrounded by the children who came from from the nearest school.