It’s not a happy start to 2017 for Labour. A report by the Fabian Society has deemed the party “too weak” to win an election – even if it doesn’t happen until 2020. It argues Labour’s best chance is to govern in coalition with other progressive parties.

Meanwhile, Labour leader Jeremy Corbyn has had to field off a new attack, this time from Unite chief Len McCluskey. The prominent Corbyn backer told The Mirror that if the polls were “still awful” in 2019, everyone – including Corbyn – would have to “examine that situation”.

So how dire will the coming years be for Labour? Here are the numbers you need to know from the Fabian Society report:

20 per cent

Labour’s current poll rating is between 27 and 28 per cent of the vote, which is slightly below what it polled in the 2010 election. But since the party has previously underperformed its mid-term polling, this could sink to 20 per cent in an election.

140

There are 231 Labour MPs in Parliament today. If a general election was held, this number could fall to as low as 140, based on current polling.

44 per cent

These are the 44 per cent, or 4m, people who voted for Labour in 2015, but a year and a half later say they would not vote for the party today. Some of this group have switched allegiance to other parties. Roughly 2m say they are undecided or will not vote. Labour’s loyal voters amount to just 5.1m people. So is it Corbyn's fault? According to this YouGov poll, conducted at the height of the Labour leadership contest, it would seem so. However, Labour in Scotland was also decimated in the aftermath of a referendum.

2010

Labour’s support doesn’t actually look that different from 2010 (when it lost its majority), but here’s the crucial fact – this statistic only applies in England and Wales. Despite losing to the Conservatives nationwide, Labour actually gained seats in England and Wales in 2015. So what's the problem, you ask?

Zero

The first problem is Scotland. Labour lost all but one of its MPs in 2015, while the SNP cleaned up. Current polling suggests if there was a general election tomorrow, the party would have zero Scottish MPs. And as for the second...

40

On current polling, Labour looks likely to reverse some of those 2015 England and Wales gains, to the tune of losing 39 seats (plus one in Scotland). This is worse than going back to 2010 – 24 seats worse, in fact.

2.1m

Among those who say they will vote Labour, an estimated 2.1m are “soft” voters who haven’t chosen one of the main parties in an election before. Whether or not they get out of bed on the day and make their x in the box is yet to be seen.

400,000

Labour has lost roughly 400,000 votes to the Liberal Democrats since 2015, compared to 200,000 each to the Tories and Ukip. This suggests Ukip is less of a threat than commonly believed. On the other hand, the Lib Dems will take Labour votes while the Tory party, second in many marginal constituencies, will snap up seats.

94

If Labour were to gain a majority at the next general election, the party would need to not only reverse the current losses predicted, but win 94 more seats (at the last election, that number was 68).

48

But if this wasn’t grim enough, the bad news for Labour is that only 48 seats are considered genuinely marginal (i.e. a 5 per cent swing would be enough to win), compared to 74 in the last parliament.

8.7 per cent

The national swing Labour would need to win an election with a majority of one is 8.7 per cent. By contrast, in the 2015 election, Labour only needed a 4.6 per cent swing. In other words, if you thought 2015’s election campaign was tough, the party is nearly twice as far from winning this time round.

30

If Labour accepts it can’t win the next general election, and agrees to work with other anti-Conservative parties like the SNP and the Lib Dems, it could kick the Tories out with a shared majority of 30 seats.

According to Andrew Harrop, the general secretary of the Fabian Society and author of the report, this is the glimmer of hope.

He said: "Labour may end up winning only 140 to 200 big city and ex-industrial constituencies, but it will have a platform from which to rebuild. On the other hand, if Labour’s fortunes recover sooner, while there is no chance of a majority, the party might be able to gain sufficient MPs to govern in partnership

with other parties.

"That should be Labour’s goal."