The SNP's rise is partly down to the unelectability of its political opponents and the country has not become a one-party state, according to deputy leader Stewart Hosie.

The MP for Dundee East defended his party’s decision to scrap its previous self-denying ordinance on voting on England-only matters like foxhunting, insisting the SNP would support policies that were “self-evidently progressive”.

With 54 out of 59 MPs and on track, according to some pundits, for another landslide victory in the Holyrood elections in May, the SNP chief was asked in an interview with the BBC Radio’s World at One, if such dominance was unhealthy for democracy.

“The issue here is we are not in a one-party state the way some of our opponents want to talk about; we are in a multi-party democratic system,” said Mr Hosie.

He added: “The fact that the other parties are effectively unelectable isn’t really our responsibility or fault.”

Mr Hosie also denied the Scottish Government was, in some regards, more austere than the Conservative Government in London when it was pointed out that it had been calculated NHS spending in England over the last few years up to 2016 was due to rise six per cent but in Scotland by only one per cent.

The deputy party leader queried the numbers but insisted health spending north of the Border was on the rise.

Now the SNP has displaced the Liberal Democrats as the UK’s third party at Westminster Mr Hosie was asked if the Nationalists’ stronger presence in the House of Commons had changed the culture of Westminster.

“We’re certainly a unified party, a united party. We turn up in the chamber and do our work and I’m always struck by how many people actually say: goodness gracious, you guys were in the chamber taking part in the debates.

“There’s an old joke going around that we’ve ‘weaponised turnout’. Our MPs have turned up to do their job and many were surprised about how few of our political opponents can be bothered to turn up for things they don’t deem to be that important.”

For many years when the SNP had just six and not 50-plus MPs they made a point of not voting on so-called England-only matters but by participating to stop foxhunting south of the Border the position changed.

Mr Hosie defended the change of tack, saying his party was “clear we wanted to try to bring progressive politics to the UK”.

He went on: “So where there’s a self-evidently progressive thing to do like keeping the ban on foxhunting, we signalled our intent to take part in that and…lo and behold, the Government buried it.”

The MP stressed how his party stood at the General Election on an anti-austerity ticket and denied the assertion that in some regards the SNP’s record was one of more austerity than the UK Government, saying he was “always surprised the way our political opponents want to pick on our record”.

But when it was pointed out that the Nationalists were in government in Scotland, Mr Hosie said: “Absolutely right. They need to get it right; we’ve had real terms increases in health spending; it is up to £12bn this year, £13bn next year.”

Yet it was noted how the respected think-tank, the Institute for Fiscal Studies, had calculated that between 2009 and 2016 health spending in England would rise by six per cent but in Scotland over the same period by just one per cent.

Mr Hosie replied: “Well, I’m not sure whether that’s revenue or capital or both. I don’t know whether that includes the additional cash we’re putting in, for example, to fund health and social care because the boundaries between the NHS providing that and councils have now gone.”

It was suggested the SNP Government had made the situation harder in Scotland for local authorities because of once again freezing council tax, which meant they could not raise extra funds to meet the rising cost of social care.

“Councils have frozen the council tax and the Scottish Government have funded that every single year; that was the right thing to do,” declared the SNP spokesman. He said they were helping families in difficult times.