The hardest lesson Labour must learn is that this Copeland loss wasn't all Corbyn's fault – and can't be solved by him leaving

Those who believe that getting rid of Jeremy Corbyn would magically serve up future Labour victories on a platter are willfully blind to the longstanding issues that have been impacting Labour support since Tony Blair's landslide victory in 1997.

It is a misdiagnosis to suggest that in removing Jeremy Corbyn, Labour will automatically find itself fighting fit. Our party faces unprecedented questions in an unprecedented time. And those who promote quick-fix solutions only further discredit our party and our cause.

The truth is that the fight to win the country from the hands of Theresa May's Conservatives would be no easy task for any Labour leader, especially just after the controversial Brexit vote. Anyone who tells you otherwise is lying to you.

This loss in Copeland cannot – and should not – be understated, however. For a governing party to gain a constituency from the sitting opposition at a time when the country is in crisis over Brexit and the NHS is being decimated is evidently worrying. Just as Corbyn's opponents offer Corbyn alone as the reason for Labour's defeat, it would be wrong of me as a supporter to offer everything but Corbyn as the reason for Labour's defeat.

For too long, Corbyn and his team have failed to take necessary risks. In appearing reticent or ambiguous on the issue of immigration, he has allowed himself to be portrayed in the press as someone who has no idea what he’s doing. And in failing to either court the media or to attempt to prove right-wing tabloids wrong, he has left even his most ardent supporters disappointed.

Rather than being risk-averse and shy of controversy, Corbyn must actively court it if our movement is to succeed. Throughout these by-elections, he failed to do that. A bold strategy that seeks greater communication with the electorate at the sacrifice of Westminster engagements should be central.

But Corbyn's strategy is something that can be easily amended. What cannot be easily changed overnight is the historical trend of dwindling Labour support since Blair won huge majorities and then failed to radically reform many areas of our country, leaving millions of voters behind between 1997 and 2010. Labour's share of the vote in Copeland has been in decline since then, and last night’s result fits perfectly within the pattern.

The decline in Labour support in these areas did not start when Jeremy Corbyn was elected Labour leader; it started when a New Labour project took hold of our party and decided to ignore working class communities across the country. The fragility of Labour's core vote in Scotland and the North was an issue long before Corbyn arrived as an easy scapegoat for the existential crisis that we face as a party. It would also be wrong to deny the impact of a concerted effort by members of the Parliamentary Labour Party to undermine Jeremy Corbyn since the day he was elected. Indeed Peter Mandelson proudly admitted recently that he works "every day to undermine Jeremy Corbyn."

Historical trends do not excuse what happened, but they do help to explain it. It is Corbyn's job as leader of our party to reverse this trend and he must now rip up the rulebook and attempt a radical way of doing politics in these most unusual of times. Trying to tone down the message is the wrong way to go about things – as we’ve seen across global politics this year, there is an appetite for change.

I expect that the mainstream narrative will be entirely different from this assessment. But I don't bring up historical factors to absolve Corbyn of blame. I bring them up because the only way Labour will win again is if it is serious about the problems that actually exist. It is true that the Labour Party will always be bigger than one man – or woman – and that is also true for the problems that it faces.