The row over MPs’ pay has sparked a debate about what kind of people we want to represent us.

The Independent Parliamentary Standards Authority (IPSA) has proposed a pay rise of 11 per cent, an idea rejected by the leaders of all three main parties.

But the regulator said it had been warned that “if MPs’ pay does not keep up with that of certain professions, or senior roles in the public sector, we risk Parliament’s returning to the Victorian era, when the majority of MPs were independently wealthy”.

Are we in danger of returning to parliaments dominated by the rich if we don’t boost politicians’ salaries?

Or do we already have a parliament of toffs? What do we actually know about the background of the people who govern us?

Age

The age of the average MP at the time they were elected has hardly changed at all over the last few decades. In 1979, 1997 and 2010 the average new MP was 49, with a few months’ difference either way.

The last election saw the biggest intake of 18-29-year-olds – 15 MPs. But that may well be a statistical blip. There’s no evidence of a consistent rise in young parliamentarians since 1979.

By contrast, the number of MPs aged 70 or over has risen at every one of the last five elections, reflecting the country’s ageing population.

Ethnicity

As with women, representation has improved dramatically over the last quarter of a century. Some 27 non-white MPs were elected in 2010, compared to 4 in 1987.

That means about 4 per cent of MPs are non-white, compared to about 9 per cent of the British population.

The Lib Dems have never managed to get a non-white MP elected at a general election. Parmjit Singh Gill won the Leicester South by-election in 2004 but lost the seat the year after.

Men and women

Women are still under-represented in the House of Commons. Only 22 per cent of MPs elected in 2010 were female.

But this demographic is changing faster than almost any other. From 1945 to 1983 women MPs numbered only in the 20s – a measly 4 per cent or so of all MPs.

Things have changed rapidly over the last half-dozen general elections. The biggest jump came in 1997, when the number of women in the Commons doubled from 60 to 120, 101 of them Labour’s so-called “Blair babes”.

While Labour have had more female MPs than any other party in 16 out of 18 post-war elections, the Conservatives in fact scored the biggest percentage increase in the number of women in successive parliaments when they nearly trebled their tally in the 2010 election, going from 17 women to 49.

Education

The Conservatives have always had the biggest percentage of privately-educated MPs, but the percentage has fallen from nearly three-quarters (73 per cent) in 1979 to just over half (54 per cent) at the last election, according to the Sutton Trust.

About 40 per cent of Lib Dem MPs elected in 2010 went to private schools. They are the only party that has seen this percentage rise over the last three elections.

A relatively small percentage of Labour MPs are privately educated and there has been little change over the years. In every parliament since 1979 the percentage of Labour MPs who went to fee-paying schools has fluctuated between 14 and 18 per cent.

This is still substantially higher than the national average. Only about 7 per cent of the general population go to fee-paying schools, according to the Sutton Trust.

But research by the social mobility think-tank also shows that private education exerts less of an influence over the House of Commons than other elite institutions.

In all, 37 per cent of MPs from the three main parties went to independent schools. In a survey of nearly 8,000 influential people, Sutton Trust found that 63 per cent of leading lawyers, 60 per cent of the senior ranks of the armed forces and 59 per cent of business lawyers were privately educated.

Figures for who went to Oxford and Cambridge follow almost exactly the same pattern: Labour’s numbers are relatively low and static; the Conservatives still have the highest percentage, but it has shrunk significantly; the Lib Dems are in the middle but there has been little change over the last three elections.

Occupation

The legal profession continues to be over-represented in the Commons, with barristers and solicitors making up nearly 14 per cent of the numbers, according to the House of Commons Library. In 1979 it was just over 15 per cent.

Tony Blair’s landslide victory in 1997 saw the teaching profession enjoy a bit of a moment in the political spotlight, with a record 20 per cent of MPs coming from the education sector.

For the first time, there were more ex-teachers than business people in the Commons (18 per cent). By 2010 the pendulum had swung back: only about 8 per cent of MPs were former school or college teachers and 25 per cent came from the world of business, the biggest percentage since 1987.

Hidden in these House of Commons Library figures are two big changes in British political life.

There’s been a big rise in the number of people already working as a politician or a political researcher when elected.

People who were already working in politics now occupy 14.5 per cent of the Commons benches, a proportion that has quadrupled since 1979.

And the fact that David Cameron, Ed Miliband, George Osborne and Ed Balls all worked as political advisers before seeking election suggests this group may have an influence disproportionate to its numbers.

The other big changes is that the number of former manual workers in parliament has collapsed from nearly 16 per cent in 1979 to just 4 per cent in 2010.

Bankers vs trade unionists

The Smith Institute adds some more detail about the latest parliamentary intake, although there’s no historical context, and the figures are not comparable with House of Commons library stats.

The think-tank found that 15 per cent of all MPs elected in 2010 came from the world of finance (banking and accountancy), including a full 27 per cent of Conservatives.

Some 7 per cent of MPs were employed by a trade union before winning a parliamentary seat. All of them were Labour, and former union employees accounted for a full 18 per cent of Labour’s ranks in the Commons.

The verdict

It may not come as a shock that the average British MP is a 49-year-old white male who is five times more likely to have gone to a private school than the average voter.

If the Smith Institute’s research is correct, more than a quarter of Conservative MPs worked in finance before the 2010 election, while nearly a fifth of Labour MPs were employed by a trade union.

But some things have changed dramatically. While women are still under-represented, the number of female MPs has rocketed in recent years, and every election brings a rise in the number of non-white members.

The figures for what jobs MPs were doing before they got elected tell some important stories too: the rise of the professional politician, the continuing dominance of the professions and the business world, and the dramatic decline in the number of people from the manual worker class who make it to the corridors of power.

By Patrick Worrall