In a letter to Labour’s general secretary, the Bourne Supremacy star wrote of the ‘disillusionment’ many Scots feel for the party

The X-Men and Bourne Supremacy actor Brian Cox has quit the Labour party and joined the Scottish National party.

Cox, originally from the nationalist stronghold of Dundee and an outspoken member of the Yes Scotland campaign, attacked the “empty rhetoric of leading members of the party” and said they no longer stand for social democracy.

Tens of thousands of Scots joined the SNP following its failed bid for independence and Cox said his decision reflects the “disillusionment” many Scots now feel for Labour. Dundee was one of the few Scottish constituencies to vote for independence.

In a letter to the Labour general secretary, Iain McNicol, Cox wrote: “The people in Dundee, particularly in the Labour party, showed great fortitude in their choice of socialism and independence and are very much on the right road. Their position was severely undermined by the empty rhetoric of leading members of the party. This has led to great disillusionment with the party throughout Scotland and my position merely reflects that disillusionment.

“I always believed the Labour party stood for social democracy but sadly, I no longer believe they do and, as I say, it is with deep sadness that I am resigning from the party – a party I believed in but has now failed in the last few years to live up to its basic principles.

“I feel the Scottish National party is the party taking forward values of social justice and represents Scotland’s best interests and that is why I have, like many other Labour supporters, decided to become a member of the SNP.”

Joe FitzPatrick, SNP MSP for Dundee City West, said: “Brian Cox joining the SNP is a fabulous endorsement for the party.

“His deep-held beliefs and passion for social justice are well-known, and it is an honour to have such a talented and internationally celebrated actor as a member.

“Labour has, as Brian points out, abandoned the principles which it used to stand for – no wonder so many former Labour members have joined and are continuing to join the SNP.

“The SNP are taking nothing for granted and we will work extremely hard for every vote and seat, because if a team of SNP MPs can hold the balance of power at Westminster, we can deliver the policies and powers Scotland needs to help build a fairer and more equal country.”