Danny Tommo admits slashing migrant boat in the Channel, sentencing on 18 November

The activist known as Danny Tommo has pleaded guilty to criminal damage after cutting a migrant boat with a knife in the English Channel. The Mirror, the Independent and Metro all reported that he changed his plea to the single charge on Thursday, appearing by video link from prison at Portsmouth Crown Court.

Judge James Newton-Price KC set sentencing for 18 November. Thomas, whose real name is Daniel Thomas and who is 37, remains in custody until then.

What did Danny Tommo admit?

He admitted one count of criminal damage. The Mirror described him as a far-right activist who was live-streaming from a boat in the Channel when the incident took place on 22 September.

According to the prosecution account given at an earlier hearing at Basingstoke Magistrates' Court, Thomas had taken a boat into the Channel and watched as the occupants of a dinghy were helped by the RNLI, Border Force and the French Coastguard. Prosecutor Kevin Lucie told the court that Thomas instructed his boat to be steered towards an empty rigid inflatable that was adrift. He then armed himself with a knife as rescue crews also approached the dinghy and a Frenchman boarded from a rescue vessel.

What was he heard saying?

The Independent and Metro reported that after cutting the boat, Thomas could be heard saying "This is what needs to happen to everyone in these boats". He also told people to get off the boat, said it was English territory and no longer France, and said the boat should be taken back, according to their reports.

The Mirror quoted Mr Lucie as telling the earlier hearing that the boat could be heard leaking air while a rescue worker was on board. It also reported that Thomas was later arrested at a BP petrol station before being taken into custody, and that he was seen dabbing his eyes with a tissue during that hearing.

Is there another charge?

Yes. At Thursday's hearing Thomas repeated his not guilty plea to a separate charge of failing to give police the PIN to his phone. That charge falls under Section 53 of the Regulation of Investigatory Powers Act 2000. The court withheld his address at an earlier hearing.

How long could he be jailed?

The maximum penalty depends on the value of the damage, according to the Sentencing Council. If the damage is worth more than £5,000, the maximum is 10 years' imprisonment. If it is worth less than £5,000, the maximum is a fine and three months in jail.

The value is not settled. At Thomas's first appearance at Portsmouth Magistrates' Court, it was heard that the cost of the damage could not be said to be above or below £5,000 because the boat had been taken back to France, the Independent reported.

Thomas will receive credit for pleading guilty, which is normally reflected in the sentence. The sources do not specify how much credit he will get.

Why does it matter?

The case turns on a question that affects the outcome: whether the damage to the boat is judged to be above or below £5,000. That figure decides whether the offence carries a ceiling of 10 years or of a fine and three months in jail. It also shows how a rescue operation in the Channel can become the subject of a criminal prosecution when a third party interferes with a vessel.

The Mirror reported that one of Thomas's children and several media representatives were among those in the public gallery at the earlier plea hearing.