Tom Watson’s comments today that a future government would have to try to reform freedom of movement rules in the European Union are clearly a last-ditch attempt to show the party’s voters that it is taking their anger about immigration seriously. But they are also strange, for three reasons.

The first is that it is strange to be talking about a future renegotiation when the Remain campaign does still occasionally try to persuade voters that they are voting to stay in a reformed European Union. By talking about what more needs to be done, Watson is effectively dumping all over the renegotiation that David Cameron has already carried out, saying that there will need to be another one. He told the BBC today that ‘with freedom of movement, it’s one issue that’s coming up on the doorstep. A future government - whether it be Labour or Conservative - has to hear what voters are telling them and if you look across the continent of Europe, voters are telling political elites the same thing.

‘So to me it’s inevitable that whoever wins the next General Election will have to make it their negotiating position when it comes to future European reform and David Cameron has the opportunity to do that as Prime Minister now if he makes it the priority for Britain’s leadership of the presidency of the EU next year.’

The second reason that it is odd that Tom Watson is making these comments is that it is surely impossible for any government, even one that puts more effort into its renegotiation than David Cameron did into his, to fundamentally reform a fundamental part of the European Union such as freedom of movement. So why start promising it?

And finally, it is odd that Labour seems so spooked by its voters being angry about immigration this late in the campaign when it has been aware of this as an issue for years. Caroline Flint warned this morning that her party's interventions on this issue often looked tactical - and this is surely another example of that.

If this is the EU referendum equivalent of the Vow in the Scottish referendum, then it isn’t quite as dramatic or convincing. And there doesn’t seem to have been a co-ordinated effort with the Tories, either, to make this a real Vow.

The effect of promising more changes in future will surely be that voters wonder whether staying in the European Union is riskier than leaving it, the risk being that no government will ever be able to secure the changes that voters want. If David Cameron couldn’t do it, how can anyone else manage it? Remain needs something seriously potent at this stage to change the debate - and this isn’t it.