An entirely pro-Europe BBC panel will have free rein to discuss the EU referendum just eight weeks before voters across the UK go to the polls, despite impartiality guidelines that require balanced coverage.

BBC Scotland is due to host two leaders debates ahead of May's Scottish election, including one on 1 May in which all five panellists will be campaigning for the UK to stay within the EU. The only Scottish party leader backing a Leave vote, UKIP's David Coburn, has not been invited.

The debate falls within the official 10-week campaign period for June's referendum on EU membership – which begins on 14 April and runs all the way through to voting day on 23 June – during which time the BBC is required to produce impartial coverage between the Leave and Remain sides of the argument.

The BBC Trust's guidelines for the Holyrood election state: "If the election period overlaps with the referendum period on EU membership, content producers must also take account of the referendum guidelines and ensure due impartiality is achieved with regard to both votes."

However, BBC Scotland has confirmed that the five pro-EU leaders in Scotland – SNP leader Nicola Sturgeon, the Conservatives' Ruth Davidson, Labour's Kezia Dugdale, Lib Dem Willie Rennie, and Green co-convener Patrick Harvie – will be free to discuss Europe when they meet on 1 May.