SNP MPs are among the most eager tablers of House of Commons motions - accounting for almost 44 per cent of all so-called early day motions (EDMs) put down since the General Election last May.

The cost to the taxpayer of Nationalist MPs’ enthusiasm for EDMs so far in this parliamentary session is at around £165,000 based on the most recent estimated administrative cost for tabling a parliamentary motion. If this rate continued, then the overall cost by the end of the five-year parliament could, among SNP MPs alone, approach £1 million.

EDMs allow members to raise any subject matter they wish; many relate to local constituency issues. But they are rarely debated at Westminster.

According to the Commons website the average cost of tabling one is £290, which is the most recent estimate; albeit one that dates back to 2005/6.

So far in this parliamentary session 1328 EDMs have been tabled, costing the public purse based on this most recent estimate around £385,000. The SNP’s group of 54 MPs - just eight per cent of Westminster’s 650 MPs - has been the prime sponsors of 578 of them. The Nationalist MP who has tabled the most, 56, is Paul Monaghan, the MP for Caithness, Sutherland and Easter Ross.

The issue of EDMs has proved controversial in the past, when, before online use became popular, costs were much higher due to an increased level of printing. In 2010, they cost £1 million a year.

In 2013, the Commons Procedure Committee published a report on EDMs and recommended no change, saying they continued to be “popular and remain a valuable tool for those MPs who use them”.

But some MPs have expressed opposition to them, believing them to be “trivial and narcissistic” and simply a means of congratulating local constituents.

Conservative backbencher, Sarah Wollaston, the MP for Totnes in Devon, who chairs the Commons health committee, has said they “cost a huge amount to administer each year and I do not think they are good value for money”. Describing EDMs as effectively MPs’ petitions, she said they had now been superseded by No 10 e-petitions, which “can be signed by everyone”.

The subject matter of EDMS ranges from the serious to the not so serious.

For example, SNP MPs have tabled motions about benefits sanctions, homelessness, the Syrian civil war and the EU referendum.

Among the latest from an SNP MP listed on the parliamentary website is one tabled by Angus Brendan MacNeil, the Western Isles MP, who wrote: “That this House congratulates the Scottish Parliament for its eye-catching end to the session, prior to the May elections, with parliamentarian and piper Stuart MacMillan piping the parliamentarians from the chamber.”

An SNP spokeswoman defended her party’s frequent use of EDMs, saying: "It is no surprise SNP MPs top the list of active parliamentarians at Westminster.

“Early Day Motions are just one of the many ways that the SNP's MPs can ensure the voices of their constituents and local communities are heard loud and clear at Westminster; our very active MPs also lodge parliamentary questions, take part in debates, question UK government ministers and perform committee work.”

She insisted SNP MPs were holding the Tories to account and standing up for individual constituents after generations of Scottish Labour MPs had sat on their hands. Their activity, she pointed out, had been praised by the Commons Speaker and had even “caught the attention of the Queen”.

The spokeswoman added: "Ian Blackford MP's EDM 1235, which seeks to annul the freeze on pensions for British citizens living overseas, is a fantastic example of how EDMs can be used to demonstrate cross-party support in the House of Commons as the motion has been signed by 93 MPs from eight different parties, including members of the Conservative Party.”