The National Theatre has been saved from significant cuts by the unstoppable commercial success of War Horse, new figures have revealed.

The theatre's annual report showed in detail just how much of a cash cow the production has become – and how the forthcoming play One Man, Two Guvnors could prove just as lucrative.

"We have not had to make any cutbacks because of the Arts Council cuts," the NT's director, Nicholas Hytner, said. "Running an organisation like this, there is a constant striving for efficiencies and increasing productivity … but we have used War Horse as our cushion."

War Horse, an adaptation of Michael Morpurgo's 1982 novel, opened at the NT in 2007. More than 1.4m audience members have since been moved to tears during performances in London and New York.

The £3m-a-year profit from the West End version more or less balanced a loss in grants from Arts Council England. The play is doing well in the US, where the NT hopes to generate about £2m a year.

The rollercoaster could continue after the release of Steven Spielberg's film version, scheduled to be released in cinemas on Christmas day in the US and in January in the UK.

One Man, Two Guvnors, starring James Corden, opens in the West End in November for 16 weeks and has already taken £2m in advance ticket sales – "astonishing," said Hytner. Corden and the cast are expected to take the play to New York in April.

The NT's executive director, Nick Starr, said the theatre had become good at exploiting its successes. Asked to engage in a what-if game – what would have happened if the NT had not generated the War Horse cash? – Starr said it could not have staged its epic production of Ibsen's Emperor and Galilean and it might not have put on the revival of Arnold Wesker's The Kitchen with its cast of more than 30. Hytner added that it might have had trouble kickstarting NT Live – with plays beamed direct to cinemas – a project that now covers its costs.

The report showed the total paying audience for NT productions in 2010-11 was 1.6 million and £70.6m was generated in a year that included Rory Kinnear in Hamlet and Danny Boyle's production of Frankenstein.

As the NT published its annual report, eight other London venues announced an unprecedented collaboration to stage eight productions during Olympic year.

The World Stages London project is a partnership between theatres including the Young Vic, Theatre Royal Stratford East and Sadler's Wells.

David Lan, the project's co-director, said the collaboration meant they had been able to create a programme that included the first stage version of Jung Chang's bestselling book Wild Swans, Simon Stephens's Three Kingdoms and a Peter Brook production of a South African fable, The Suit.

The team behind the Port Talbot The Passion will also present a sire-specific Babel, which will have a cast of 500 professional and community performers.