Around 50 people were expected to move onboard the vessel, docked in Portland Port in Dorset, on Monday after weeks of delays to the scheme.

Cheryl Avery, the director for asylum accommodation at the Home Office, said the first "cohort" had been "successfully onboarded", but there had been "some challenges".

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Those currently on the barge are expected to stay there for between three and nine months while their claims are processed, she added.

The Bibby Stockholm is one of a number of alternative sites the Home Office is using to end reliance on expensive hotels for asylum seekers, which the government says is costing £6m a day.

However, there has been considerable local opposition due to concerns about the asylum seekers' welfare and the impact on local services.

Protesters gathered at Portland Harbour on Monday with welcome packs containing toiletries and contact details of organisations offering support to migrants.

Care4Calais claimed it had stopped around 20 asylum seekers from various locations from boarding the barge, including people who have disabilities, people who have had traumatic experiences crossing the sea and victims of torture and modern slavery.

The charity said it will continue working with asylum seekers who don't want to be moved into the accommodation.

Ms Avery said she could not go into details about individual legal cases, but the offers of housing on the barge were on a "no choice basis".

She would not confirm when the Bibby Stockholm would reach its 500-person capacity but said that a "phased and controlled approach" would be taken.

The 222-bedroom barge will ultimately hold 500 single males, with numbers expected to increase gradually over time.

There have been delays to moving people to the site after safety concerns were raised, with the Fire Brigades Union branding it a "potential death trap" and warning about the risk of overcrowding.

Downing Street suggested Home Office minister Sarah Dines misspoke when she said earlier on Monday that the accommodation could reach full capacity by the end of the week.

Asked about the comment, the prime minister's official spokesman said: "We are looking to (reach) that number over time - I don't think we are aiming to do it by the weekend."

Ms Dines told Sky News the barge "sends a forceful message" that people who cross the Channel will be housed in accommodation that is "proper... but not luxury" - claiming hotels are part of the "pull" factor attracting people to the UK.

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Hotels now housing 50,000 asylum seekers

The arrival of people at the barge coincided with a release of data by the government showing the number of asylum seekers living in hotels - paid for by the taxpayer - had climbed to more than 50,000.

Labour contrasted this with Home Secretary Suella Braverman saying there were 40,000 people in the accommodation in December last year.

In total, 50,546 people were being housed in hotels as of 30 June 2023.

This comes after Rishi Sunak promised to "stop the boats" in January. In December last year he claimed in the House of Commons that his government had "already identified locations that could accommodate 10,000 people" - and was planning to find more.

A total of 339 people crossed the Channel on Friday and Saturday, with none making the trip on Sunday during bad weather.

Total arrivals so far for 2023 stand at 15,071, which is 15% down on last year, the latest figures suggest.

However, that is significantly higher than the 10,703 arrivals that had been detected at this point in 2021.

Shadow home secretary Yvette Cooper said: "Rishi Sunak is failing to fix the Tories' boats chaos and the Conservatives are just flailing around chasing headlines rather than getting a grip."

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Steve Valdez-Symonds, Amnesty International UK's refugee and migrant rights director, said: "It seems there's nothing this government won't do to make people seeking asylum feel unwelcome and unsafe in this country.

"Reminiscent of the prison hulks from the Victorian era, the Bibby Stockholm is an utterly shameful way to house people who've fled terror, conflict and persecution."

He added that "rather than wrecking the asylum system", the government "should fairly and efficiently determine people's claims instead of perpetuating costly backlogs, human misery and organised criminal exploitation".

Alongside the barge, the government wants to house people in military sites and marquees.

Multiple reports have also suggested the government is re-visiting plans for a processing centre in Ascension Island in the South Atlantic Ocean, if the long-touted Rwanda deportation scheme does not get off the ground.

Home Office minister Ms Dines would not confirm or deny the plan but said the government was "looking at all options".

She said on Monday morning "times change" and that the small boats crisis had become "urgent" when asked why the plan was reportedly being reconsidered after seemingly being rejected by Boris Johnson's former government.

Downing Street also refused to be drawn on the "speculation" and said it is confident its plan to deport people to the east African nation will be successful in the courts.

This week is the government's unofficial "small boats week", where it wants to talk about its efforts to get a grip on the number of people crossing the English Channel on a small boat.

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Labour's Ms Cooper added: "The prime minister admitted last December that hotel use was a serious problem and promised to end it, but instead since then it has gone up by a truly shocking 25% with more asylum hotels still opening, and the taxpayer having to pay billions more pounds as a result.

"This is the direct consequence of Tory mismanagement and their disastrous failure to speed up asylum decisions or clear the backlog which is still at a record high."