After a disappointing result for Labour in the Sleaford by-election on Friday, over the weekend it fell on Diane Abbott and Ken Livingstone to take to the airwaves to try and generate some good PR for the beleaguered party.

However, things didn't go quite to plan as Abbott -- the shadow home secretary -- attempted to attack the Conservatives for in-fighting over Europe while not being able to say what Labour's position was. Nick Robinson -- standing in for Andrew Marr -- went on to read quotes from different Labour politicians raising concerns about Jeremy Corbyn's position on freedom of movement:

“ NR: This is why people talk about confusion. The man who is running for mayor in greater Manchester -- Andy Burnham -- says freedom of movement has been defeated at the ballot box it is clearly no longer an option. You're saying it is an option?

DA: We believe in regional autonomy, but the truth is you cannot have access to the single market without a measure of freedom of movement.

NR: What about Carwyn Jones, he accuses you of having a very London-centric position...

DA: Wales and the West Country and the North East are some of the parts of the country that have the most to lose by coming out of the EU.

However, aside from ongoing mystery about Labour's take on Brexit and immigration, the most telling moment concerned Labour's dismal showing in the polls. With a YouGov voting intention poll putting the party on a seven-year low at 25 per cent, Abbott was asked when Corbyn's leadership could be judged ineffective. While she refused to use such terms, she did give him a deadline to fix things -- predicting that Labour will close the gap in the polls with the Tories within the next 12 months. Over on the Sunday Politics, Ken Livingstone, too, offered this time frame. The former Mayor of London said that 'if it’s as bad as this in a year’s time, we would all be worried'.

Whether Abbott meant to or not, Corbyn is now on notice. If the Labour leader can't turn his party's fortunes around in the next twelve months there will be a case for another leadership challenge -- and this time it might not come from the right of the party.