Foster returned from "retirement" in 2007 with an aim to win an Olympic medal at the 2008 Olympic Games.Returning to the British squad he won a silver medal in the 50 m freestyle at the 2008 FINA Short Course World Championships, and qualified to represent Great Britain at the same distance in the Olympics.Foster has openly criticised Sweetenham's management style and Sweetenham ensured that he was not selected.
In 2004, Foster faced the disappointment of not being selected for the Olympic Games.
At the British Olympic Trials, he won the 50 free in 22.49 seconds, well under the Olympic qualifying standard but seven hundredths of a second below the standard National Team Director Bill Sweetenham had set for inclusion in the British Olympic Team.
Despite success at Commonwealth, European and World championship level mostly at short courses, Olympic titles eluded him and he has never won a medal.
Some have suggested that he has never quite achieved his full potential, arguing his maverick approach to training and preparation cost him an individual Olympic medal, as long course events are more challenging and require more disciplined training approach for success.
On 12 February 2009, Foster co-presented BBC Look East's 6.30 pm bulletin, with Susie Fowler-Watt.
Foster was a contestant on the BBC One programme Let's Dance for Sport Relief as a member of the dance group 'The Olympians'.
In terms of medals and longevity (1986–2008), he is amongst the most successful British swimmers of all time.
He was the fastest swimmer in the country by age 15.
Mark launched Mark Strong Coaching & Training in 2004 to help employees at creativity companies around the world to become the best versions of themselves.