SNP MP Pete Wishart has said winning a second referendum on Scottish independence is “all about gentle persuasion”.

The Perth and North Perthshire MP said in a blog post on his website that talk of “illegal referendums” and “dissolving the Union” would lead to people who voted SNP for the first time in this month’s General Election turning their backs on the party.

A motion from Inverclyde Council leader Chris McAleny and Na h-Eileanan an Iar MP Angus MacNeil at the SNP conference in October pushed for a “Plan B”, stating that a win for the SNP at the next Westminster or Holyrood election would give the Scottish Government a mandate to open talks on exiting the UK.

Wishart, however, says in his blog that persuasion is required to win people over to the case for independence and that the SNP must fight the urge to hold a referendum quickly – which he said would play into the hands of the UK Government.

He wrote: “Talk of illegal referendums, UDIs (unilateral declaration of independence), dissolving unions and trying to game or trick our way to independence will send all these aspiring recruits running back into the arms of the Union case. The Tories are hoping beyond hope that we now blow it through impatience and alienate this new support that is coming our way.

“Instead it should now be all about gentle persuasion, about convincing and understanding.”

Wishart added that a big win for the independence cause in a future referendum would “put it beyond all reasonable doubt and question”. He said: “There is a real sense that we are in the end game of Scotland’s participation in their Union. It really now is only ours to lose. We now have the opportunity not just to win it but to win it well and put it beyond all reasonable doubt and question.”

Meanwhile, independence group Forward As One has set up a crowdfunder to take the UK Government to court if Boris Johnson formally rejects First Minister Nicola Sturgeon’s request for a Section 30 order. The campaign, which aims to raise £40,000 to take legal action at the Court of Session, has so far reached just over £9000.

Forward As One says on its campaign website: “The aim is simple, to defend the inalienable right of the Scottish people to engage in the fundamental right to vote on the constitutional question without reliance on any politician to ensure that those rights are enabled.”