Oil magnate Sir Ian Wood dipped a toe in the debate on Scottish independence yesterday by suggesting oil reserves off the Scotch coast may tail off by 2035.

He told the BBC: “Oil and gas will deplete. Scotland cannot count on significant oil and gas revenues to Treasury, I’m going to guess probably after 2035, 2040, as you go into a whole lot of marginal fields.”

He added: “In an independent Scotland forever, we must take that into account.”

The boss of British oil giant BP Bob Dudley agreed, saying in a statement: “BP has been in the UK North Sea for 50 years and we hope to operate here for many years to come. However, the province is now mature and I believe Sir Ian Wood correctly assesses its future potential.

“The opportunities today are smaller and more challenging to develop than in the past.”

BP has come out in favour of the union.