Somerset star Marcus Trescothick has backed England's decision not to allow Kevin Pietersen to return home during the West Indies tour.

The former captain wanted to leave the Caribbean between Tests because of home sickness.

Former Test batsman Trescothick twice went home early on previous England tours because of a stress-related illness before calling time on his international career last year.

He said: "I don't know the exact details but there would have to be a very good reason for wanting to go home for a couple of days.

"We all know what those sort of reasons are and they don't need to be said, but if there wasn't that then I don't think going home would be the right thing to do."

But Trescothick still feels sympathy for Pietersen. "I know what the guys go through in an alien environment," he said.

"There is no denying the Caribbean is a nice place and it was my favourite tour, but people are different.

"He had a tough couple of weeks and people don't realise what the off-field stuff takes out of you.

"Losing the captaincy was probably the biggest issue of his career so far and he has done OK but he hasn't gone as well as he normally has.

"We have just got to cut him some slack. We all know how much we need him firing and we just have to give him a break and nurse him through it.

"The wickets haven't been anyone's kind of wickets. It hasn't been entertaining cricket.

"So much has gone on for England in the last six months with Michael (Vaughan) going and the Pietersen-Peter Moores issue. That is a distraction they don't need because it is mentioned in every interview."

Trescothick thinks Australia are slight favourites ahead of the Ashes but insists that could well change before the first ball is bowled at Cardiff on July 8.

"I don't think we will know until it gets going," he said. "Michael Vaughan could make a couple of hundreds and get back in the side and we will see who picks up wickets in county cricket.

"Looking at results you would probably say the Aussies are slight favourites, but it can change so quickly.

"It only needs them to lose one player or our players to find form and anything can happen.

"I watched most of the cricket this year to see what is going on. Australia weren't going that well before Christmas but they have turned it around in South Africa and it is funny how it goes.

"The South Africans felt the pressure at home whereas they didn't away.

"I have never faced Mitchell Johnson but he seems to have improved a lot and has developed the inswinger which he didn't have before

"I watch it all on the telly but it gives me no indication that I want to go back.

"I want to go for as long as I can for Somerset. I am 33 now and if I can go until I am 40 that will be my first target.

I have to keep my mind and body fresh. After that every year is a bonus."