In January 2006, ITV screened a pilot episode of a new TV drama called Lewis and waited anxiously for the viewing figures to come in.

They were not disappointed. The pilot, shot on location in Oxford, was seen by 11.4 million viewers, making it the most watched drama of the year across all channels.

And a new series of four episodes will be hitting the small screen on Sunday night.

But the project almost didn't happen because of Kevin Whately's resistance to follow up the hugely popular Inspector Morse series, based on the novels of Oxford author Colin Dexter.

When John Thaw died from cancer in February 2002, two years after the last episode of Inspector Morse was screened, it looked like the end of the popular two-hour dramas among the dreaming spires.

But the success of the pilot confirmed the suspicions of the programme makers - that the general public missed Morse so much that they would welcome the promotion of Sgt Lewis to a leading role.

Further episodes of Lewis were shown in February and March last year and the viewing figures were healthy enough to merit a second series.

This time round, Kevin Whately is again joined by Laurence Fox as his young colleague DS Hathaway.

Clare Holman returns as pathologist Dr Laura Hobson, and Rebecca Front is back in the role of Lewis's boss, Chief Supt Jean Innocent.

Guest stars include Rachael Stirling, Oliver Milburn, Neil Pearson, Pippa Haywood, Cheryl Campbell, Kwame Kwei-Armah and Tim Dutton.

In this series, havoc reigns in the religious community of Oxford, risking the emotional and physical well-being of DS Hathaway.

During the filming, Mr Whately had to put his back into the role when he found himself carrying his co-star downstairs to rescue him from a burning house.

He said: "It was hot as hell.

"Half of it was shot in the studio and half of it was shot on location in Jericho. Out on location you could feel the heat 100 yards away.

"But when we were filming in the studio it got hotter and hotter and as it was burning gas the fug got worse and worse.

"We were on a very narrow staircase and, although Laurence is 6ft tall, luckily he is quite light and skinny so it wasn't so bad lifting him. However, for the actual stunt bits with the flames I had to carry an actual stuntman in case his hair caught fire over my back! He was at least three stone heavier than Laurence."

He added: "Because of the way Lewis is written, my character has even more to say than John Thaw as Morse used to.

"When Laurence is in it's great because he is bouncy and full of energy and keeps the crew going. They are in every minute of every day.

"We just have different ways of working. Laurence is switched on when the camera is on him, but can switch off the moment it isn't and be the party animal, which is great.

"He is very good with the guests like I used to be on Morse, he chats to them and makes them feel very comfortable, which lets me get on and concentrate."

Mr Whately told the Oxford Mail he had seen many changes during the 20 years he has been filming in Oxford.

"There always seems to be building work going on these days, but then some of those colleges have been there 600 years or more," he said.

"I love snooping around the renovations because you can see the stonemasons chipping at the gargoyles and so on.

"One of the great things about filming a drama like Lewis on location, is being able to go to all these stately homes and fabulous old buildings and poke around in other people's living space. I really like that rather than being stuck in a studio."

He added he could remember the old Morse days with more clarity than the last episode of Lewis he filmed.

"I bore Laurence rigid with it saying I filmed a scene with Richard Griffiths here' or this is where John Gielgud and I'. Must be an age thing!"

Executive producer Michele Buck added: "Lewis has a special place in the hearts of the ITV audience.

"This is partly because of the gentle nature of the show - the films are elegant rather than violent.

"The crimes are intriguing and complex, rather than shocking and brutal, which is another key to its success.

"Oxford adds a certain class to the drama and the university background gives it an academic halo."

Lewis is produced by Chris Burt, who worked on 11 Morses. Executive producers are Michele Buck, Damien Timmer and Ted Childs.

*The new series of Lewis starts on Sunday on ITV1 at 9pm.