The European Commission has cleared Shell's proposed takeover of Enterprise Oil.
It says the move will not create anti-competitive effects in either the oil and gas transportation or crude oil processing markets in the UK.
The Commission says that after the merger sufficient independent infrastructure capacity will remain to enable offshore field owners to continue developing new fields.
It found the merged company will have an equity interest in only one processing facility and a limited number of pipelines.
It said sufficient capacity will remain in the pipelines and processing facilities.
The new company will be unable to control access to the infrastructure and so foreclose third party access, the Commission said.
The same applied to the markets for transport and processing natural gas, it said.