Marek was elected a member of Ceredigion District Council in 1979 and served until 1983; he was chair of its finance sub-committee in the year 1982–83.

This move, and his frequent criticisms of the Labour-led Wrexham County Borough led to his deselection as the Labour Party's candidate for the National Assembly elections of 1 May 2003.

Later that year he formed a new political party called Forward Wales (Welsh: Cymru Ymlaen).

[4] He ran for re-election in the 2007 Welsh Assembly election, but was defeated by Labour's Lesley Griffiths by 1,250 votes, thanks to a swing to the Conservatives, Liberal Democrats, and UKIP.

[6][7] Marek is one of three Welsh MPs or AMs to win a constituency as both a party candidate and an independent, following S. O. Davies who was MP for Merthyr Tydfil from 1934 until his death in 1972, who was deselected by the local Labour Party on grounds of age prior to the 1970 general election but ran against the official candidate as an independent and won; and Peter Law who was barred from contesting his seat for Labour due to an all-woman shortlist being imposed [8] In 2006, Marek was appointed as Vice President of Wrexham A.F.C.