John Sergeant after training with his dancing partner Kristina Rihanoff

At 64 he will be the most senior celebrity in the forthcoming series of Strictly Come Dancing.

But John Sergeant is making no allowances for his age after adopting an intensive training schedule for the show.

The former political editor has been hard at work perfecting his routines for up to five hours a day and from the look on his face as he leaves the dance studio, the strain is taking its toll.

Sergeant has attended the gym sessions in West London religiously every day, arriving at 10am and not leaving until 3pm.

A local said: 'He normally goes in carrying lots of papers and looking pretty grumpy.

'By the time he comes out again he is red-faced, sweaty and usually apparently on the brink of exhaustion.

'He does have quite a satisfied look on his face though.'

Sergeant, who spent 40 years as a journalist, has said that he asked for his costumes to make him look 'taller and slimmer'.

Despite his devotion to physical exertion his new regime appears to have made little impact on his rather portly physique.

This could be down to his lunchtime visits to a restaurant opposite the gym which specialises in 'wraps, steaks, burgers, fajitas and cocktails'.

Sergeant has freely admitted that he is an unlikely candidate for ballroom dancing and expects to benefit from 'the sympathy vote'.

Sergeant showing the strain and, right, heading for lunch

A 'self-confessed non-dancer', he has been nicknamed Twinkletoes by his agent since he agreed to participate.

He has already injured both feet during rehearsals, as did Kate Garraway last year when she won huge public support despite her lack of dancing talent.

He said: 'I have had more injuries doing Strictly Come Dancing than I had when I was a war correspondent for the BBC.

Costume finery: John and Kristina in their gladrags

'The show has turned out to be more dangerous than covering the war in Vietnam.'

Sergeant has been married for nearly 40 years and he and wife Mary have two adult sons who also work in television.

After leaving the confines of Westminster five years ago, he admitted: 'Maybe what I needed in life was a bit of absurdity.'

The political commentator, famously bundled out of the way of Margaret Thatcher by press secretary Bernard Ingham in 1990, has been paired with Siberian-born professional dancer Kristina Rihanoff for the sixth series of Strictly Come Dancing, which starts on September 20.

He will take on 15 other contestants including the Olympic swimmer Mark Foster, singer Rachel Stevens, rugby player Austin Healey and Gary Rhodes, the celebrity chef.

Others taking part include actors Don Warrington, Jessie Wallace and Gillian Taylforth, and models Jodie Kidd and Lisa Snowdon.

His partner Miss Rihanoff said loyally: 'John's been great. He's been working hard and concentrating on lessons. I couldn't ask for more.'

Sergeant is not the oldest contestant to take the floor on Strictly Come Dancing.

Jimmy Tarbuck appeared two years ago at the age of 66, but was forced to pull out of the competition on medical advice.