THE SNP has suffered a further drop in membership, new figures have revealed.

After topping 120,000 in July last year, it slipped to 118,000 last month.

The figures, which have not been publicised by the party, are revealed in a briefing paper published by the House of Commons library.

The SNP still has comfortably more members than all the other Holyrood parties combined.

READ MORE: Labour stalwart David Martin calls for coalition with SNP at Holyrood

However its rivals said the slide confirmed Scotland had now passed “peak Nat”.

The SNP dared the other parties to publish their own membership numbers.

The fall coincides with Nicola Sturgeon calling a second independence referendum in March, and the party losing a third of its MPs in the June election, its worst reverse in 40 years.

The SNP’s membership grew exponentially in the wake of the No vote of 2014.

In December 2013 it was 25,642. A year later it was 93,045, and 115,102 a year after that.

READ MORE: Anas Sarwar under pressure after family firm refuses to say if it recognises trade unions

In July last year, the SNP business convener Derek Mackay boasted the membership was a record 120,203, up 4000 since the EU referendum.

“The incredible upsurge in SNP membership shows no signs of stopping,” he said.

“This extraordinary increase in membership makes clear that it is the SNP which people trust to stand up for Scotland’s best interests.”

However the "incredible upsurge” has stopped.

By December 2016, membership was down to 118,959, and it has kept falling.

The Commons paper states: “There are around 118,000 members of the Scottish National Party, as of August 2017, according to information from the party’s Central Office.

“This was a slight decrease compared to almost 119,000 members in December 2016.”

Like other parties, the SNP is under no obligation to issue membership figures.

READ MORE: Labour stalwart David Martin calls for coalition with SNP at Holyrood

When membership was rising, its chief executive Peter Murrell, regularly released figures on Twitter and at the party’s conferences.

However Mr Murrell, who is married to Nicola Sturgeon, has not done so for some time.

Across the UK, Labour is the biggest party, with around 522,000 members in June; while the Tories had 149,800 in December 2013, the most up-to-date estimate published by Tory HQ.

The LibDems had 102,000 members in May this year, the Greens 65,000 had across the UK in March; Ukip had 39,000 at July 2016; and Plaid Cymru had 8,300 this year.

The SNP’s recent annual accounts for 2016 also revealed a drop in membership income.

READ MORE: Anas Sarwar under pressure after family firm refuses to say if it recognises trade unions

These showed membership income, which fluctuates according to how generous members feel, stood at just over £2.5m last year, some £156,500 less than in 2015.

A Labour spokesperson said: “This looks like the shine is coming off the SNP from the highs of 2015. Maybe lots of members are seeing through the radical language to the reality - a centrist, managerial government."

A spokesman for the Scottish Conservatives said: “As well as losing votes and seats in both parliaments, the nationalists are now losing members. We are now past ‘peak Nat’.

“It seems the SNP’s arrogance on the constitution is driving away even those who once regarded it as a party worth being a member of.”

An SNP Spokesperson said: "Unlike other political parties, we’re happy to publish the figures in full. Less than three years ago, SNP membership stood at 25,000. Today it’s 118,000.

"Perhaps the Scottish branches of the Labour and Tory parties would care to follow our lead and tell people what their own figures are?

“If they refuse, then people will draw their own conclusions.”