The Unite union is planning an industrial action ballot following an overtime dispute.

Drivers deliver to customers from 14 manufacturing sites across the UK.

Among the firms biggest customers are Travis Perkins and Jewson.

The strike threat has “disappointed” Marshalls bosses.

Susie Fehr, Group HR Director said: “Marshalls has for many years enjoyed a collaborative and supportive relationship with Unite, as the principle union represented within the business.

“Late last year during the annual pay negotiation there was discussion regarding a number of other issues including this specific issue of overtime.

“Unite decided to take this issue off the table on the basis that it pertained to a limited group of employees.

“The result of the annual pay negotiation was that an increase of 2.5% was agreed.

“The company remains committed to finding an appropriate internal solution and most recently communicated with the impacted employees on 11th April and are looking forward to the ongoing dialogue.

“Marshalls is therefore disappointed that the Union has decided to pre-empt these discussions and has not raised this as a formal dispute.”

Unite national officer for building trades, John Allott said: “We are preparing to hold an industrial action ballot on the inequality in overtime rates between the drivers and the manufacturing workforce.

“The two biggest customers of Marshalls – Travis Perkins and Jewson will be severely hit, with a big ripple effect on their own customers, if strike action goes ahead.

“We call on the company to sit down and negotiate on the issue of our members’ overtime pay, so we can reach a fair settlement.”