Wiseman profits were boosted by a new contract with the Co-op
East Kilbride-based dairy firm Robert Wiseman has reported an 81.5% rise in first half pre-tax profits, to £21m.
The company said an increase in sales volumes of 11.3% was due to new contracts with the Co-op and two Spar wholesalers.
The group has raised its interim dividend to 5.75p a share, compared with last year's 5p.
However it warned that higher oil prices would put pressure on profits in the second half of the year.
In its outlook, the company said it had seen "a return of significant oil-related costs" which would push the price of plastic and diesel upwards.
It estimated this could add £4m to costs in the second half of this year and despite an expected improvement in bulk cream prices, the company said: "It may be difficult to maintain the short-term operating profit per litre levels seen in the first six months."
The group said the increase in volume in the first half of the year provided a number of challenges.
Workers at the group's English dairies were put on a 7-day week to fulfil demand.
However the firm plans to increase the volume at its new Bridgwater dairy in Somerset and its Amesbury site in Wiltshire.
Chief Executive Robert Wiseman said: "With the completion of the investments at Bridgwater dairy and Amesbury depot we are well placed to continue the growth in volumes and to improve operating margins in the medium-term."
The company is recruiting 300 workers for its distribution site at Amesbury.
The group also announced that Jack Perry would join the board as a non-executive director in March next year.
Mr Perry recently stood down as chief executive of Scottish Enterprise.
In a statement the company said: "Mr Perry brings a wealth of corporate experience to the board and we look forward to benefiting from his services."
The Robert Wiseman group supplies more than one in every four litres of milk consumed in the UK.
It operates from seven dairies and 15 processing sites and employs more than 4,500 staff.
The firm was founded by Robert Wiseman Snr - the current chairman's father - in 1947.