Market analysts weighed in on the significance of BP's exit.
"It says a lot when BP isn't prepared to stick around to see if the new government can re-energise the UK's energy policy," said Chris Beauchamp, Chief Market Analyst for IG.
Beauchamp suggested bureaucratic delays influenced the timing.
"Clearly BP thinks it will take too long at a time when the need to exploit new energy fields is pressing, and waiting around for Whitehall to move is not a prudent use of resources," he said.
In a separate move, BP revealed a global downsizing plan affecting its production and operations segments.
"We are building a simpler, stronger, more valuable BP," a spokeswoman said.
The cuts would impact about 8 percent of non-frontline workforce globally.
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"As part of this process, we are proposing changes that would result in a reduction in roles, intended to reduce complexity, improve accountability and support long-term performance in a changing market environment," she said.