Shadow Chancellor John McDonnell has promised to give financial and political support to Cuba’s brutal Communist regime under a future Labour government.

The vow comes despite widespread accounts of arbitrary detention, beatings and political repression.

Standing in front of a Che Guevara flag, senior Left-winger Mr McDonnell said that Britain under Labour would be the repressive state’s ‘staunchest ally’.

Founded after a revolution led by Fidel Castro (pictured above), Cuba has been a Marxist-Leninist one-party state since 1959 and Castro’s brother Raul took over as President in 2008 until last year

In a speech last week to the Cuba Solidarity Campaign, his promise to stand with Cuba in the face of sanctions by US President Donald Trump was in stark contrast to Mr McDonnell’s recent attempts to reassure the City that a future Labour government would not have a hidden radical agenda.

The news came on the same day that Mr Trump banned US cruise ships from calling at the island state, to ‘keep US dollars out of the hands of Cuban military, intelligence and security services’, according to US Treasury Secretary Steven Mnuchin.

Cuba is regularly criticised by human rights campaigners for its poor record, and the most recent report from Human Rights Watch (HRW) catalogued more than 2,000 incidents of arbitrary detentions between January and August 2018.

An HRW account said: ‘Detainees are often beaten, threatened and held incommunicado for hours or days. Police or state security agents routinely harass, rough up and detain members of the Ladies in White – a group founded by the wives, mothers, and daughters of political prisoners – before or after they attend Sunday mass.’

Amnesty International’s 2017/18 International Report added: ‘Arbitrary detentions, discriminatory dismissals from state jobs and harassment in self-employment continued to be used to silence criticism.

‘Advances in education were undermined by ongoing online and offline censorship. Cuba remained mostly closed to independent human rights monitors.’

Founded after a revolution led by Fidel Castro, Cuba has been a Marxist-Leninist one-party state since 1959 and Castro’s brother Raul took over as President in 2008 until last year.

And addressing Cuba’s ambassador to London, Teresita Vicente Sotolongo, at the Rail and Maritime Transport Union’s Cuba Garden Party, Mr McDonnell said: ‘When the Election comes and I believe when a Labour government is elected, not if, we will be your staunchest allies to support the Cuban revolution. That means political support but it means also support, financial and on trade, to ensure that we prevent any attacks on Cuba that Trump may launch, economically or politically, or any other form. We stand with you comrades.’

The news came on the same day that Mr Trump banned US cruise ships from calling at the island state, to ‘keep US dollars out of the hands of Cuban military, intelligence and security services’, according to US Treasury Secretary Steven Mnuchin

His speech was greeted with rapturous applause from the 200-strong crowd before Mr McDonnell posed for pictures for one of Cuba’s tightly controlled newspapers as attendees chanted ‘Viva Cuba’ and ‘Viva socialismo’.

The event, held at the headquarters of the RMT, one of the most militant and Left-wing trade unions in Britain, saw delegates waving Cuban flags while a Cuban flag also flew from a pole atop the building.

Guests at the event in Clapham, South London, enjoyed a free bar, a hog roast and even indulged in Havana cigars at £10 each, as well as music from a Cuban salsa band and the raffle prize was two return air tickets to Cuba.

The speech came just two weeks after Mr McDonnell distanced himself from the Cuban regime, claiming ‘it was never socialism’ in an interview with The Times.

His speech at the RMT HQ drew fierce criticism, with Conservative MP Andrew Lewer saying: ‘It is shocking that Mr McDonnell is promising British taxpayers’ support to the failed Cuban communist dictatorship, which locks up its political opponents and whose repressed people do not even have enough food to eat.’

Dr Julian Lewis MP, chairman of the Defence Select Committee added: ‘With John McDonnell, as with Jeremy Corbyn, what you see is what you will get.’

He added: ‘They have always held these pro-Marxist views and they always will.’