Ukip leader Nigel Farage has insisted his party is relevant to Scottish politics as he prepares to target SNP voters in a Holyrood by-election.

He claimed membership was growing, days before he is due to visit Edinburgh and announce who will stand in the Aberdeen Donside contest.

"We are growing in Scotland and have every intention of winning seats, both at Holyrood and in next year's European elections north of the Border," he said.

He dismissed the Edinburgh establishment as "divorced from reality" and claimed key Ukip issues such as immigration resonate with the public more than mainstream parties think.

Aberdeen Donside appears solid SNP territory according to the 2011 Holyrood election, won by Brian Adam with 55% of the vote – almost double that taken by the nearest Labour challenger. Mr Adam, who had cancer, died last month.

Attempts by Ukip to win a seat at Holyrood appear at odds with its 2010 General Election manifesto, which pledged to replace the 129 MSPs with Scottish MPs.

Ukip also argued in favour of downgrading Holyrood's powers.

Labour, the Conservatives and Liberal Democrats have announced their candidates. The SNP is expected to put forward North East MSP Mark McDonald in the next few days.