A third series was planned but John Simm was so exhausted from carrying the entire series - appearing in every scene - that he refused to do another. Instead, the idea was retooled to feature another character going back in time and so Ashes to Ashes (2008) was born, a series that lasted for three seasons instead of the two of its parent show. Simm later admitted that he regretted his decision and that he would love to play Sam Tyler again if this show would be continued in some way.
M.A.R.S stands for Metropolitan Accountability and Reconciliation Strategy.