A paramedic who was called to give assistance to the Lib Dem AM Mick Bates after a night out says he was physically assaulted by him.

The medic, who is planning to press charges, said he was punched in the chest by an "abusive" Mr Bates outside a Cardiff restaurant last month.

Montgomeryshire AM Mr Bates has said he cannot remember what happened.

On Monday, he stood down as chair of the assembly's sustainability committee and also from party front bench duties.

The paramedic, who does not want to be named, said he was part of an ambulance crew called to Charlestons Brasserie in Caroline Street, Cardiff, at around 0230 GMT on 20 January.

He said the crew found Mr Bates, the Lib Dem's spokesman on sustainability and rural affairs, had a minor head wound which it was said he sustained falling down the stairs while being ejected from the premises.

According to the paramedic, Mr Bates delivered a tirade of verbal abuse, and punched him in the chest while he was trying to administer first aid.

He said a police officer was called into the ambulance to give Mr Bates a warning, but the AM was not arrested.

The paramedic said that the abusive behaviour continued at the accident and emergency department, where Mr Bates was kept under observation by security.

He said: "When the ambulance got there, the male was very aggressive, verbally aggressive, lashing out with his both arms, telling us to clear off.

"It was at that point we were approached by another male who said that the injured party was an AM who worked for the Welsh Assembly Government.

"We tried to assess the injuries on the gentleman, to which we had nothing but abuse."

The paramedic said the team decided to take Mr Bates to hospital but he resisted attempts to put him into the ambulance in a wheelchair.

He said: "We continued to try and get the appropriate care for the gentleman as he had a minor head injury.

"We established that the gentleman wasn't knocked out at any point whatsoever by an independent witness.

"On trying to obtain observations on the gentleman, he's grabbed out at a jacket, punched myself to the chest and grabbed my colleague's wrists."

He said a police officer was called into the ambulance at this point and Mr Bates was issued with a warning.

'Babysat'

"We arrived at the (University of Wales Hospital) with him still swearing, being abusive and, again, in the hospital he had to be babysat in the centre of the resuscitation area by security due to his behaviour."

The Liberal Democrats have said they are investigating they allegations about Mr Bates.

Welsh party leader Kirsty Williams had said she was trying to establish the facts and that she had understood Mr Bates had been knocked unconscious, suffering a serious head injury.

She had said: "I've spoken to Mick Bates - he's apologised if his behaviour following the incident has caused any concerns."

In a statement on Monday, a spokesperson from the Welsh Liberal Democrats said: "Following a conversation between Kirsty Williams and Mick Bates they have agreed that he will be relieved of his front bench duties and his chair of the sustainability committee whilst this matter is being investigated.

"We have informed the [Cardiff and Vale] university health board and ambulance service that both Mick and the party will fully co-operate with any investigations.''