The two have been added to the list of high-profile speakers at this July's festival which comes on the back of last year's record-breaking fortnight.

But already the Festivities are warning they fully expect this year to be tough.

Festivities director Amanda Sharp stressed it was nothing dramatic, but said she felt the public should be aware of the worsening financial pressures the Festivities operated under.

"Despite continued generous support from a number of loyal local businesses, this year is proving a difficult one in terms of raising sponsorship and business membership – and this is on the back of a number of years with similar difficulties," she said.

The current financial climate has affected the level of support received from small and big businesses – which increases the gap between box-office receipts and the cost of presenting the festival.

"As a result of our accumulated funding difficulties, we are expecting to have to dig into our reserves quite significantly this year," said Miss Sharp.

"We have been preparing ourselves for this eventuality but, while we can definitely weather this for one festival, it is certainly not a situation we would ever want to continue."

On the plus side, Miss Sharp said she was delighted with the programme which has come together for this year (June 27-July 13).

Miss Sharp added: "The 2007 Chichester Festivities saw a 20 per cent increase at the box office. Some 143 ticketed events were presented to audiences of more than 30,000 at 27 venues in and around the city so we're pulling out all the stops to try and better that this year."

Undoubtedly, a highlight will be a rare talk by former hostage Alan Johnston, the BBC correspondent who endured 114 days in captivity at the hands of the Army of Islam (The Venue, July 13).

Following on from David Dimbleby's talk last year will be brother Jonathan Dimbleby (July 1) speaking about his journey across the nine time zones of Russia to film a key new BBC TV series.

Other talks have a distinct Asian flavour. Historian and travel writer John Man will talk about China's Great Wall and Terracotta Army while Chinese writer Sun Shuyun talks about Tibet and the 18 months she spent with a film crew in a remote Tibetan village; Michael Wood speaks about his epic BBC series The Story Of India and Lesley Downer gives an illustrated insight into the culture of Japan in the light of her first novel The Last Concubine.

Further talks will be given by former MP Oona King and The Guardian's drama critic Michael Billington while broadcaster John Humphrys tackles religious beliefs, following on from his book and provocative Radio 4 series Humphrys In Search Of God.

Already announced are Sixties singing star Lulu (Chichester Cathedral on July 9) and Lovetrain – a salute to the music of the 1960s and 70s – at Goodwood Racecourse on June 27.

To book call 01243 780192 from June 2.