In a last-ditch attempt to get her deal through parliament, Theresa May has presented a supposedly fresh 10-point plan to break the deadlock. On closer examination, the changes are at best slight, and at worst set to lose her more support than they gain. May once attempted a similar manoeuvre over supposedly “legally binding changes to the backstop”. This afternoon was a last hurrah that is set to fail precisely because what she has offered is substantially no different to her three previous attempts to get a withdrawal bill passed. Nothing has changed.

The most eye-catching announcement was that MPs would be offered a parliamentary vote on a second referendum if they supported the bill at its second reading. But most pro-referendum MPs have concluded that the best chance of getting a majority for a second national vote would be in October, in the face of a fresh Tory leader genuinely willing to crash out of the EU with no deal. They know that without brinkmanship, the numbers simply aren’t there. So May’s offer won’t wash.

In another faux-concession, the prime minister has offered a vote on customs between a “facilitated customs arrangement” and a temporary customs union, lasting until the next general election. But the former has already been rejected by the EU as unworkable (it has never been attempted anywhere in the world) and the latter is essentially what is already in the standstill transition in the withdrawal agreement. So in fact, this is no concession at all, and one of the main reasons that talks with the Labour party broke up without agreement.

May has also attempted to placate Brexiters in her own party by offering new assurances on the backstop. The problem is that her proposal is likely to make the situation worse from the perspective of the Eurosceptic ERG, not better. In the absence of any known solutions to the Irish border problem, the backstop isn’t a fallback but rather the default, so the new commitment to present alternative arrangements by 2020 is virtually meaningless. The agreement might as well require the UK government to present the European commission with a jar of magic beans or arrive at the next summit on a flying carpet. May’s fresh commitment to avoid divergence between Northern Ireland and the rest of the UK when the backstop is activated means that the whole of the UK would be a rule-taker from Brussels through Belfast.

Finally, the new commitment on workers’ rights and environmental protections represents vanishingly little movement from the government. While workers’ rights are promised to remain the same as those in the EU, environmental protections are essentially the same as in the withdrawal agreement, with a commitment not to slide back. It seems highly unlikely that these changes will satisfy either trade unions or environmental groups, further reducing the likelihood that opposition MPs will back the bill.

These latest parliamentary manoeuvres do not change the parliamentary arithmetic. For every vote that the prime minister picks up from Labour MPs from leave constituencies, she will lose at least the same number from her own side of the house. Even her own cabinet are not prepared to support this new endeavour. With Tory MPs anticipating their future leader to be committed to a no-deal exit in October, they have little incentive to change their position. It seems quite likely that the margin of defeat will be greater than the last attempt. Given the lack of substantive changes and the low likelihood of successful passage of the bill, there is little reason for opposition MPs to back an outgoing prime minister when they will face extraordinary opprobrium from their own party members and supporters for doing so. Most parliamentarians on all sides will be thinking a simple thought: please stop, now.

• Tom Kibasi is director of the Institute for Public Policy Research and chair of the IPPR Commission on Economic Justice