FOOTBALL legend Sir Alex Ferguson has become the first named donor to the Better Together campaign after giving £501 to mock the SNP demand for a £500 cap on donations from England.

The Labour-supporting Manchester United manager gave £1 more than the SNP's desired limit to the pro-Union campaign as a tongue-in-cheek "symbolic gesture".

The donation followed calls from the SNP for both sides in the early phase of the campaign to accept a voluntary limit of £500 on donations from voters outside Scotland.

Ferguson said: "Scots living outside Scotland but inside the UK might not have a vote in the referendum, but have a voice and we care deeply about our country. I played for Scotland and managed the Scotland team. No-one should question my Scottishness just because I live south of the Border."

Meanwhile, it has emerged that ministers could face a legal challenge if they insist on lowering the spending limits for the independence referendum, contrary to proposals from the Electoral Commission.

The pro-Union No campaign warned last night that the proposed limit would "stifle debate".

Better Together raised the prospect of legal action as it published a scathing submission to the Electoral Commission on how the final leg of the campaign in 2014 should be financed.