Oil and gas operators in the North Sea plan to lay off one in six UK-based workers this year as industry confidence remains low, a survey has found.

The latest industry study is the "most negative" yet, according to a partner at its sponsors, law firm Bond Dickinson.

The report found three-quarters of North Sea oil and gas contractors are "less confident" about their prospects than they were a year ago, although confidence levels have marginally improved from their record low in November.

Operators surveyed reported a 15% fall in UK staff in the past 12 months and expect a further 17% of staff to lose their jobs this year - almost triple the 6% predicted six months ago.

For contractors, there was a 13% reported weighted average reduction in their UK-based headcount in the 12 months to March 2016

About one in four companies (24%) said their top priority is cutting costs, while 42% cited increasing efficiency and productivity as their main concern.

The joint survey by Aberdeen and Grampian Chamber of Commerce and the Fraser of Allander Institute found 14% of contractors reported working at or above optimum levels in the UK Continental Shelf compared to 79% three years ago.

The level of demand, commodity price and economic climate are cited as the top factors limiting activity in the North Sea.

Some 42% of firms expect to reduce investment in the next two years, while 12% plan to increase it.

One projected area of growth is decommissioning, with 85% of contractors expecting to increase their involvement in this sector in the next three to five years - up from 79% six months ago.

Questioned on the EU referendum, 45% of respondents said it was difficult to reach a clear view over whether or not a Brexit vote would be positive for the industry, 20% said it would make little difference, 27% said it would be "unhelpful" and 7% believed it would be positive.

Uisdean Vass, oil and gas partner at Bond Dickinson, said: "Six months ago I described the 23rd Oil and Gas Survey as the most negative we had experienced. Unfortunately this, the 24th survey has surpassed it.

"The uncertainty which all those in the industry face at the moment regarding their livelihoods continues and any slowdown in the shedding of jobs does not appear to be materialising."

Russell Borthwick, chief executive at Aberdeen and Grampian Chamber of Commerce, said: "In the previous two surveys we carried out, we found confidence had hit record lows, with an all-time low in November 2015.

"This time, while the figure is still firmly in negative territory, it has marginally improved, which may perhaps show we are near the bottom of the curve."