Years ago after one of Chancellor George Osborne's early Budgets I recall attending a post-event wash-up attended by his Labour predecessor Alistair Darling, who told the audience: 'I recognise Osborne's roads funding pledge because not only did I announce it when I was Chancellor but I believe I also announced it when I was previously transport secretary.'

Retread spending pledges are a notorious aspect of government smoke and mirrors in which ministers re-announce spending commitments to sound like they are generously funding public services without any new money so as not to upset the Treasury. Gordon Brown as Chancellor was an expert at retreads.