"The most sensational result in British by-election history, bar none," was George Galloway's proud boast on being declared Bradford West's new MP. Well almost, and, perhaps more importantly, maybe not the most significant by-election success ever.

Click HERE to view 'In numbers: Bradford West' graphic

At 36.6 per cent, the swing from Labour to Respect was enormous. But it did not quite match Labour's worst-ever drubbing, the 44.2 per cent swing it suffered at the hands of Simon Hughes in Bermondsey in 1983. Indeed, the 20.4 point drop in Labour's own vote was quite modest by the standards of previous disasters, including the party's first ever defeat at the hands of the Scottish National Party in Hamilton in 1967 (-29.7) and its equally unexpected loss of Brent East (-29.4) to the Liberal Democrats shortly after the 2003 Iraq war.

Moreover, this was not the first time that someone other than a Conservative, Labour or Liberal Democrat managed to win an English post-war by-election. That accolade was claimed nearly 40 years ago by Dick Taverne when, following deselection, Lincoln's sitting Labour MP opted to resign his seat and defend it as "Democratic Labour". At 58.2 per cent, Mr Taverne's share of the vote was even slightly bigger than Mr Galloway's 55.9 per cent.

This was not the first time either that Bradford West's substantial Muslim population – second only in size to that in Bethnal Green and Bow – where Mr Galloway was elected for Respect in 2005 – has behaved unexpectedly. On the occasion of Labour's nationwide victory in 1997, the party's share of the vote fell in the constituency by nearly 12 points, seemingly because the Conservatives had nominated a Muslim candidate.

In truth, there are few other places where Mr Galloway's distinctive stance on Iraq, Afghanistan and the politics of the Arab world could have been expected to secure such a favourable reception. Equally, there are no other candidates on the far left with the charisma of Mr Galloway and who are likely to be capable of repeating his feat.

Even if both man and constituency are unique, the result still raises an intriguing question. Voters throughout Britain are showing an increasing willingness to vote for smaller parties. A record 10 per cent did so in 2010. In the Barnsley by-election last year, Ukip won 12 per cent and second place. Now that the Liberal Democrats are in no position to garner the protest vote, perhaps this is all disillusioned voters can do?

John Curtice is Professor of Politics, Strathclyde University

Great by-election upsets

Hamilton (Nov 1967)

A milestone defeat for Labour saw the charismatic Winnie Ewing capture the Lanarkshire constituency for the Scottish National Party. The SNP had firmly arrived on the political map.

Lincoln (March 1973)

Labour's Dick Taverne forced this by-election when he quit the party over its anti-Common Market stance and contested it under the label Democratic Labour. He stormed home with 58 per cent support.

Bermondsey (Feb 1983)

At the depth of its fortunes, Labour chose the hard-Left, gay Peter Tatchell to defend its former south London stronghold. Liberal Simon Hughes won with a 44 per cent swing – and has held the seat ever since.

Brent East (Sept 2003)

Liberal Democrat Sarah Teather (now an Education minister) exploited anger in the multi-ethnic north-west London seat over the Iraq war to seize it from Labour with a 29 per cent swing.