The party’s chair, Gareth Thomas MP said: ‘Just as co-operatives led the way on fairtrade, we are now setting the pace when it comes to tax transparency. In becoming the first political party to secure the mark, we hope to lead the way for others to follow.’

Paul Monaghan, a co-founder of the Fair Tax Mark said: ‘We have been particularly heartened to see the publication of a new tax policy that rules out the use of tax havens by the party, and added transparency around tax due on investment income. More broadly, the party’s work to support the Fair Tax Mark and other progressive programmes to tackle tax dodging has been much appreciated.’

Since it was set up two years ago, the Fair Tax Mark campaign has accredited 17 businesses including the Co-operative Group retailer, Lush Cosmetics, energy company SSE and transport operator the Go Ahead Group.