Back in 2009, as leader of the opposition, David Cameron (now bound for the Manor of Northstead) announced his intention to cut the number of serving MPs from 650 to 585 as part of wider efforts to "reduce the cost of politics". In Coalition, the Lib Dems moderated this to the 600 representatives proposed in the Boundary Commission’s plans today.

Even at the time the gesture was tokenistic – there to help the message of fiscal rectitude sink in. But beyond the speculation over individual politicians’ futures, if we accept the need to redraw constituency boundaries given population changes, and even to do so according to the electoral register (and not population estimates), the case for why we should reduce the number of MPs has not been adequately made.

Arguments then rested on the eminent political scientist Robert Dahl’s calculations that the UK was more generously represented per head of population than other countries, with one elected legislator per 91,500 people, compared with 104,700 for France, 136,700 for Germany and 673,600 for the US.

But a rather brilliant short paper from 2010 by Stuart Wilks-Heeg and Lewis Baston explodes this and other myths.

Councillors matter too

Firstly, those making the case with Prof Dahl’s statistics are missing a rather important piece of the puzzle: the significant number of federal legislators and representatives at lower levels in comparable countries. Prof Jennifer Lawless estimated in 2012 there were around 520,000 elected officials in the US, or one for every 600 people. In 2009, the BBC calculated the UK had 29,000 elected politicians – closer to one for every 2,150 people.

This is partly a reflection of our increasingly over-stretched and disempowered local authorities – while the UK has a local councillor for every 2,605 people, in France it is 116 and Germany 250.

The UK is also pretty unique among established democracies in having an executive formed entirely of the legislature – reducing the numbers of those scrutinising policy even further. This is also a growing trend, with 118 MPs currently on the Government payroll, either as members of the Cabinet, ministers or parliamentary private secretaries.

MPs will have even more work

Finally, the number of representatives has not kept pace with the rate of population change, nor the growing burden on MPs in the form of casework. The number of MPs was increased to 630 in 1955 and 650 in 1983 – it is easy to forget how radically the expectations on MPs has changed in that time. An anecdote from former MP Austin Mitchell’s Westminster Man lends a flavour:

A Labour newcomer in 1945 told of his first visit to the constituency after the election. A top-hatted station master met him to ask whether he would be following the previous Member in paying his annual visit at that time of year. A.V. Alexander hardly ever visited his Sheffield constituency during or after the war, producing such disgruntlement that his successor George Darling was selected on a radical promise of quarterly visits. When he was later appointed PPS to Arthur Bottomley, the constituency wrote to absolve him even from that promise "in the light of his heavy duties".

From the 1960s onwards, MPs were increasingly expected not just to live in their constituencies, but also to help resolve local issues. In 1992, Norris et al found that MPs spent approximately 24.5 hours a week on constituency work – one-third of their weekly working hours. This is before the advent of email, or the growth of immigration and other casework in inner cities – both labour-intensive trends identified by Wilks-Heeg and Baston, which if anything call for more MPs, not fewer.

Parliament has been emboldened recently by the growing power and influence of select committees and an independently-minded Speaker – these are trends to be encouraged. Moves to reduce the number of MPs will only reduce scrutiny on Government and increase the workload for those who remain.

So this plan should be resisted by all sides of the House, and what’s more, we should be considering steps to improve democratic governance and oversight in places other than Westminster. With all that said, what is the likelihood of Parliament refusing to pass it?

Resistance is possible

Earlier this year, an unnamed source close to the Government described the changes as the most difficult thing for them this Parliament apart from the EU referendum – and we know how that went.

Speculative analysis has suggested that Labour (23 seats), Lib Dems (4 seats, half of their total) and the SNP (6 lost in Scotland) stand to lose most from the changes, and so would be expected to vehemently oppose them. Although those within the Labour party keen on deselection of certain MPs may spot an opportunity here, the short-term tactical gain would surely be outweighed by the long-term strategic loss in any calculation.

The Labour and Lib Dem-dominated House of Lords could potentially bog down the legislation, although it did feature quite clearly in the Conservative manifesto and therefore might be considered subject to the Salisbury convention, which prevents too much Lords interference (if that still holds any sway).

But it’s worth remembering that the Government has a very slim working majority of only 17, and the very same number of Conservative MPs are expected to lose their seats. To counter this risk, this morning Sir Patrick McLoughlin, Conservative chairman, was briefing out a "no colleague left behind" strategy – where those under threat would be promised the seats of those resigning come 2020 – and Theresa May will be keen to avoid a major rebellion this early in her tenure.

So rather than self-interest, what it may turn on is the principled stand of those Conservative backbenchers who take pride in the power of Parliament to hold Government to account and would rather not see it diminished. In that way, these reforms should be seen less as the Government against the Opposition, and more the executive against the legislature.

Ralph Scott is Head of Citizenship at Demos.