Mark Stoneman, Durham's highly rated opening batsman, will join Surrey at the end of the season after turning down the offer of a new contract. The decision is a blow to Durham, with Stoneman having come through the club's academy to captain the side in limited-overs cricket.

Stoneman will link up with former Durham team-mate Mark Di Venuto, who is now Surrey's head coach. He could be followed by more high-profile departures due to the straitened financial circumstances at Durham, with Scott Borthwick, Mark Wood and Keaton Jennings among the most high-profile players out of contract at the end of the season.

Both Stoneman and Borthwick have featured in recent discussions for England selection and the county would benefit from ECB payments for their development even if they were to be called up after switching clubs.

Despite traditionally tough batting surfaces at Chester-le-Street, Stoneman has flourished over the last few years, passing 1000 first-class runs in each season since 2013. His first-class average is just 32.11 but he has been mentioned as a possible Test opening partner for Alastair Cook. In List A cricket, Stoneman averages 40.17 and led Durham to victory in the Royal London Cup two years ago.

The 29-year-old indicated that a desire to win over the England selectors contributed to his decision to move south, despite being offered a two-year deal by Durham.

"Joining Surrey under the guidance of long-time mentor Michael Di Venuto and Alec Stewart will provide the platform to reach new levels with my batting," Stoneman said. "It is a fantastic opportunity to join a young and exciting squad. I am very excited for the years ahead at the Kia Oval which is a great Test match venue and I hope my experience can contribute to a period of success for Surrey CCC.

"The desire to play for England is as strong as it has ever been and I feel that now is the right time to accept a new challenge in an environment which will hopefully see me fulfil the dream of playing for England."

Durham have also allowed Phil Mustard to leave, with his contract up at the end of the season, but Paul Collingwood will continue to play on. Collingwood, captain of the Championship side, has agreed another one-year extension, which will take him into his 22nd year as a professional.

Collingwood, 40, is currently averaging 50.66 in the Championship and saw Durham move up to second in the Division One table after a hard-fought victory over Lancashire at Southport last week.

"I am so proud to still be playing for my home county who have given me the perfect environment to fulfil all of my cricketing dreams," Collingwood said. "I feel that I can continue to contribute to the team and I really want to help develop the next generation of Durham cricketers.

"I know that this club still has so much to offer English cricket and I continue to be excited by the young talent coming through the ranks."

Mustard, who is in his benefit year, will join Gloucestershire on loan until the end of the season, meaning he is likely to miss out on a farewell T20 appearance at Chester-le-Street. The 33-year-old lost his place in the Championship team last year, briefly joining Lancashire on loan, and although he has continued to be a leading limted-overs performer, Durham have been unable to afford a new deal for him.

He joins Gloucestershire as cover for Gareth Roderick, who suffered a finger dislocation that required surgery and is expected to be out for six weeks.