As many as 120,000 oil workers will have lost their jobs in Britain by the end of the year, compared with the number of lost oil industry jobs in mid-2014 when oil prices started declining and unleashed sector-wide cost cuts, the industry's lobby group said on June 10.

Britain's oil industry and indirectly related jobs, like supply chain and services, are estimated to fall to 330,000 by the end of the year, down from 450,000 in 2014, Oil and Gas UK said in a report.

Major British oil industry employers like Royal Dutch Shell (NYSE: RDS.A), BP Plc (NYSE: BP) and Chevron Corp. (NYSE: CVX) have all announced substantial job cuts in order to rein in costs as revenues have been hit hard by weak oil prices.

Shell announced an additional 475 job cuts in its U.K. and Ireland upstream business two weeks ago as part of a global drive to shed 12,500 jobs between 2015 and the end of 2016.

"The total employment we will sustainably provide depends on the level of investment attracted into the basin," said Deirdre Michie, CEO of Oil and Gas UK. "If investment falls, then so will jobs."

Britain's North Sea, one of the oldest oil and gas basins, has been particularly strongly impacted by the market downturn as low revenue prospects are coupled with some of the world's highest E&P costs.

About half of British oil jobs are located in Scotland, and the Scottish government has set up a task force to help oil workers find employment elsewhere.