Fire Brigades Union members have been accused of using bullying tactics by sending threatening letters to part-time colleagues not supporting their pay strike.

A number of retained fire stations claim to have received letters with a Fire Brigades Union (FBU) stamp mark, containing copies of a poem called "The Scab".

The verses by the socialist Victorian writer Jack London describe a strike-breakers, or "scabs", as traitors to God, themselves and their country.

Retained firefighters will man engines

The FBU - which represents full-time workers and most others - has denied the allegation and promised to sack any fire-fighters found intimidating colleagues.

It is the latest skirmish between the two unions. as the FBU gears up for the first of six strikes next Tuesday.

The Retained Fire-fighters' Union is not supporting the series of strikes called by its counterpart, which is seeking a 40% pay rise.

RFU leader Derek Chadborn has sent an open letter to the FBU saying the mailings breach the union's own anti-bullying and harassment policy.

He also said his union would be acting unlawfully under secondary picketing legislation if they were to support a strike by another union.

Claims denied

In the letter to FBU General Secretary Andy Gilchrist, Mr Chadborn asked the union to "immediately investigate these actions and take disciplinary measures against the perpetrators".

Mr Chadborn told BBC Radio Wales envelopes which have allegedly been received by retained fire-fighters bore the franking stamp of the Welsh FBU office.

It undermines the professionalism and the strength of the case they do have for a significant increase in pay

Derek Chadborn

"I'm appalled that a professional organisation like the FBU con be party to anything like this," he said.

"I think it's completely designed to intimidate and ensure that retained firefighters follow their particular line.

"I think it undermines the professionalism and the strength of the case they do have for a significant increase in pay.

"We have never said we don't support much higher rates of pay. We totally go along with that."

Mr Chadborn said they had received complaints from RFU members from all around the country which showed actions "infringed the FBU's own policy of fairness and equality".

Claims denied

The FBU in Wales has denied sending any poems or putting pressure on the part-timers to join the strike, and said the RFU accusations are unfounded.

But the union in south Wales has promised to investigate any such reported claims and sack anyone exerting pressure on colleagues.

Firefighters are planning months of disruption

A statement read: "Any reports received by South Wales Fire Service which contravene the Brigade's Equal Opportunity and Fairness at Work Policy will be treated extremely seriously, and will be investigated promptly.

"Any substantiated allegations of bullying and harassment will be treated as gross misconduct which clearly has the potential for dismissal.

'Disrespectful' incidents

There have also been claims that part-timers have been told they would have to join the FBU to have any chance of getting a full-time job.

Those claims, too, were rejected by FBU Wales regional officer Dick Pearson.

"We have received no information, no notification from employers that retained firefighters or any firefighters have made any of these complaints," he said.

"We do take a very strong line in the FBU on allegations of bullying and harassment, a far stronger line than [Mr Chadborn's] union.

"I am categorically stating that the official line of the FBU is we do not take any intimidatory action."