Tug workers employed at the Liverpool port - as well as those in Hull and Immingham, Gravesend and the Medway, Felixstowe, and Southampton - could be balloted over strike action if their employers refuse to register them ‘on-shore’.

Adsteam are currently negotiating a merger with their main rival Svitzer, which is owned by shipping conglomerate Maersk.

Tug operators are essential workers in the UK ports. If they do vote to strike, it could mean the main ports in the UK coming to a standstill.

The Transport and General Workers Union accuse Adsteam of “trousering” savings on National Insurance made by registering the tug workers in Guernsey for the last three years. Richard Crease, the T&G chair of the Adsteam national shop stewards committee, said the proposed takeover of Adsteam by Svitzer had brought the dispute into focus.

“We have never felt happy with Adsteam moving our employment registration ‘off-shore’ and believe the time is right to restore us to the mainland.

“Adsteam seem adamant that it is not their responsibility and prefer to pass the buck to Svitzer. We don’t agree and that’s why we have a dispute which is now likely to go to a strike ballot.”

Adsteam’s chief executive Europe, Stephen Eastwood replied that “Adsteam have been considering for some time the return of employees from Guernsey to the UK.

“The transfer to Guernsey was originally made in April 2003 to take advantage of rules relating to offshore manning of British flagged vessels, which resulted in a saving in National Insurance Contributions.

“Following a change in UK Legislation, offshore manning finished in October 2003. Since that time Adsteam employees and the payroll centre have remained in Guernsey. The transfer back to the UK has some potential complications in terms of employment contracts, which need to be resolved. In principle the company has no objection to the change because it would have no benefit or detriment to either company or employees.”

Eastwood’s answer is mealy-mouthed politician-speak. Adsteam don’t want to register on the mainland because it would cost them the 12.5% National Insurance payments. A strike - which would deprive the company of profits - is the best way of making them sit up and take notice.

However, tug workers should remember the TGWU’s role in the 1995-98 Liverpool dockers’ strike, and make sure their leadership doesn’t sell them out for a knighthood and a seat in the House of Lords.