The channel took 29.4% of the audience for May, compared to ITV1's 28.4%.

This was put down to shows such as Auf Wiedersehen, Pet and Cutting It in the 6pm to 10.30pm time slot.

Cutting It was deemed a success

"The extra investment is being seen on screen and viewers are enjoying it," said a BBC spokeswoman.

ITV1 said it was easy to read too much into the figures, and said it was planning to increase programme funding.

Its budgets had been affected because its main ITV franchises, Granada and Carlton, had been funding the troubled ITV Digital.

ITV and the BBC also measure different time periods as peak-time.

'Healthy lead'

The broadcaster uses 7pm to 10.30pm, but even then it is marginally behind the BBC with ITV1 on 29.6% and BBC One on 29.7%.

An ITV spokesman said: "Across this year ITV1 has maintained a healthy lead over BBC One in peak-time so it is misleading to take one month's figures.

"The advertising recession has affected programme budgets but the recent announcement of a £25m increase in the autumn schedule signalled ITV's determination to fight back and improve its performance.

"We have a host of new programmes lined up and we are confident that the channel will maintain its traditional dominance in peak time."