The parties most likely to win the Senedd election next month offer radically different futures for Wales, but all six are facing criticism for not being “upfront” in their manifestos about the fiscal challenges the next Welsh government will face.

Labour, Plaid Cymru, Reform UK, the Green party, the Conservative party, and the Liberal Democrats are standing for the Senedd, which is expanding from 60 to 96 seats under a more proportional voting system.

Polls suggest Plaid Cymru or Reform will be the biggest party, with Welsh Labour, which has led the country for nearly 30 years, in a distant third. Coalition mathematics means Plaid is the only party likely to be able to form a government, possibly in coalition with the Greens or Labour.

This week, the Institute for Fiscal Studies (IFS) thinktank said that its analysis of the party manifestos showed “virtually no detail” on spending commitments; big public investment plans are beyond Wales’s current budgets, and will require expensive upfront private funding, or increased borrowing powers.

David Phillips, head of devolved and local government finance at the IFS, said: “The combination of a slowdown in increases in UK government funding, and growing demands and costs for health and social care, will mean a Welsh budget under significant pressure.

“Voters are already unhappy after years of only slow economic growth, a rising cost of living, and public services that have failed to recover from the Covid-19 pandemic … but the next Welsh government will have to face up to it.

“As the current UK government has found out, not preparing the public for difficult choices prior to an election can come back to bite you politically when the electoral dust has settled.”