Asylum seekers spent four days on board the Bibby Stockholm barge after Legionella bacteria was discovered, it has emerged.

Dorset Council says Home Office contractors were notified about the results last Monday – but all 39 migrants only left the controversial site on Friday as a “precautionary measure”.

The council went on to claim that a Home Office staff member was informed about the bacteria on Tuesday.

However, a government source has told Sky News that there is no record of this conversation – and claimed that the Home Office only received a written notification about the Legionella on Wednesday evening.

Legionella bacteria can cause a potentially deadly lung infection known as Legionnaires’ disease. It is contracted by people breathing in droplets of water containing the bacteria.

None of the migrants on the barge have shown any symptoms of the disease, according to the Home Office.

Ministers are facing questions about who was informed about the Legionella test results and when.

Sky News has pieced together a timeline of when Legionella bacteria was found on the barge, and how long it took before those migrants on board were evacuated.

Tuesday 25 July

Dorset Council’s environmental health department takes water samples from the Bibby Stockholm barge and sends them to the UK Health Security Agency (UKHSA) for testing in its environmental lab facility.

The tests typically take at least 10 days to complete.

Monday 7 August

Initial test results are received by Dorset Council – the same day the first 15 asylum seekers board the Bibby Stockholm.

Dorset Council said it informed CTM and Landry & Kling – the companies contracted by the Home Office to operate the barge – that same day.

A spokesperson said it was not the council’s responsibility to tell the Home Office about the Legionella, as this fell to the contractors.

Read more on the Bibby Stockholm:
What’s it like inside the barge?
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Tuesday 8 August

Dorset Council’s environment health team meet the barge’s contractors “to further discuss results”. The council said a Home Office official was “verbally informed of the test results”.

A government source told Sky News there was no record of that conversation.

A small number of asylum seekers also arrive on the boat the same day.

Wednesday 9 August

Dorset Council officers visit the barge again to take further samples and “concern about control measures” prompt it to alert the UKHSA.

The UKHSA confirmed it was contacted by Dorset Council on Wednesday evening.

Sky News has been told that the first written notification to the Home Office was also that evening.

Thursday 10 August

The UKHSA convenes an “incident management meeting” between Dorset Council, the Home Office and the contractors, as well as representatives from the NHS.

The meeting concludes no more passengers should be allowed to board the vessel while a risk assessment is carried out.

Those recommendations are later confirmed in writing to the Home Office.

A second incident management meeting and risk assessment takes place in the afternoon.

The government said it was advised by the UKHSA to remove the six people who had boarded the barge that day.

A decision to remove all 39 individuals as a “further temporary precaution” was not taken until the next day.

Friday 11 August

Asylum seekers are not evacuated from the barge until Friday – four days after Dorset Council says it informed the barge contractors about the Legionella test results, and three days after it said it told a Home Office staff member.

Dorset Council said it followed “the appropriate technical guidance throughout on what to do when a positive Legionella sample is received”.

One of the barge’s contractors, Landry & Kling, said it was “working closely with local authorities to ensure housing solutions are safe and appropriate for service users”.

Landry & Kling said it and its project partners “have followed all written recommendations made by Dorset Council Environmental Health”.

Sky News has contacted the Home Office to ask when officials were made aware of the test result and when ministers were told.

A spokesperson previously said the health and welfare of those on board the vessel “is our utmost priority”.