Between 1979 and Thursday night, the principal opposition at Westminster had only failed to defend a by-election seat successfully on three occasions.
In each case, the opposition went on to lose the subsequent general election.
So on the face of it Labour’s drubbing at the hands of George Galloway is a serious blow for Ed Miliband. Despite lengthening UK poll leads for Labour in the past week, his prospects of ever entering 10 Downing Street as Prime Minister are apparently far from good.
Yet in many respects, Bradford West was unique. It was a contest tailor made for George Galloway.
His critique of the West’s involvement in Iraq and Afghanistan together with his long-standing sympathy with the Palestinian cause and the wider Arab view of the world has ensured that his Respect party have been successful in winning Muslim support.
This was previously demonstrated by his success in Bethnal Green & Bow in 2005.
Significantly, Bradford West is second only to Mr Galloway’s former Bethnal Green & Bow seat in the size of its Muslim population – 38 per cent according to the now outdated 2001 Census. And while the wounds of Iraq have healed somewhat since Mr Galloway’s Bethnal Green & Bow victory, they have recently been replaced by newer, equally raw ones over the ongoing war in Afghanistan.
Meanwhile, there is no other politician on the left who has the charisma and oratorical skills of Mr Galloway.
Even if another by-election were to be occasioned in a strongly Muslim constituency in the near future, it seems unlikely that his success would be repeated.
Nevertheless, Mr Miliband can hardly afford to be complacent about this defeat.
When did we last hear of Labour crashing to an unexpectedly spectacular defeat at the hands of a strongly charismatic and talented politician? Why, of course, less than 12 months ago when Alex Salmond tossed Scottish Labour aside.
It seems that when presented with an apparently more attractive way of expressing their dislike of the Tory-led UK coalition many a potential Labour voter is all too easily persuaded to leave the Labour camp and back that alternative instead.
Labour’s current UK poll lead reflects disillusion with the coalition far more than any deeply felt enthusiasm for Labour itself.
The challenge facing the uncharismatic Mr Miliband is to persuade voters they really want to see him in Downing Street. after all.
• John Curtice is professor of politics at Strathclyde University