Reform UK leader Nigel Farage has proposed sending some prisoners overseas to serve their sentences, as part of a raft of measures he says would create around 30,000 prison places and cost £17.4bn.

Speaking at an event in London, he also announced plans to build five prisons, return foreign prisoners to their country of origin, and recruit 30,000 police officers.

Farage said the UK was “facing nothing short of societal collapse” and that a Reform government would halve crime in five years.

Labour said the policies were “unfunded” – while the Conservatives accused Farage of offering “tough talk without the faintest idea how to deliver it”.

Asked after his speech how the policies would be funded, Farage said tax rises would not be needed and that Reform was “advocating cutting huge amounts of public spending,” including the HS2 rail project and net-zero policies.

He said crime costed the British economy £170bn, adding: “It isn’t really a question of can we afford to do this – it is really a question of can we afford not to do this?”

Reform UK estimates its proposals would cost £17.4bn over five years, with an annual cost of £3.48bn.

Plans to hire more police officers make up £10.5bn of the overall bill.

In order to create more prison spaces, Farage said his party would use the Army to build five new low-security ‘Nightingale’ prisons on Ministry of Defence land, creating 12,400 spaces for “lower category offenders”.

The Nightingale label is a reference to the network of emergency temporary hospitals set up during the Covid pandemic.

Farage said he would be willing to force Reform-run councils to accept new prisons in their area, adding that it would bring well paid jobs to local communities.

Reform is also proposing to create 10,400 places by transferring foreign prisoners to their country of origin. In exchange, the UK would be prepared to accept British offenders serving sentences abroad, he said.

A further 10,000 prison places could be found by sending serious offenders to serve their sentences abroad, the party says.

Farage said his party would consider multiple locations and pointed to Kosovo, Estonia and El Salvador as possibilities, although when pressed on the central American country’s human rights record, he said it was an “extreme example”.

Earlier this year, the El Salvadorian President offered to take prisoners in the US – including those with American citizenship – and house them in El Salvador’s mega-jail.

Other countries have pursued similar arrangements – in 2021 Denmark agreed to pay Kosovo an annual fee of £12.8m for an initial five-year period to rent 300 of their prison spaces.

Successive UK governments have reportedly explored the idea of sending prisoners to Estonia.

The BBC has been told that both former Conservative ministers and current Labour ones came to the view that such a plan would be very expensive.

In September of last year, the government said it was “making no such plans or announcements in relation to Estonian prison places”.

A growing prison population, coupled with a lack of new prisons, has put pressure on the system.

Last year, the Prison Governors’ Association warned that prisons in England and Wales were days away from running out of space, leading to the government letting some inmates out of prison early.

Responding to the speech, Labour Party chair Ellie Reeves said Reform was “more interested in headline-chasing than serious policy-making in the interests of the British people.”

She added that Labour was “backing up its word with action,” pointing to the party’s plan to hire 13,000 more police officers and community support officers by the time of the next election in 2029.

A Conservative Party spokesperson said Farage was “offering tough talk without the faintest idea how to deliver it” adding that he had not explained how he would fund the additional prisons places.

They said the Tories would pass a law making it easier to deport foreign criminals.