The UK’s largest energy companies have withheld support for a legally binding target to reduce the EU’s emissions to net zero by 2050, even while publicly backing the plans.

Royal Dutch Shell, BP and British Gas’s owner, Centrica, have all publicly thrown their weight behind more ambitious EU emissions cuts, but none supported the Brussels proposals for a tougher target in an official consultation.

The new target, to be debated by EU leaders in Brussels on Friday, would increase the bloc’s carbon-cutting ambitions from 80%-95% below 1990 levels by 2050, to a carbon neutral target.

The European commission said a climate-neutral future is in line with the Paris climate agreement objective to keep the global temperature increase to well below 2C and pursue efforts to keep it to 1.5C.

Although BP and Shell have both voiced public support for the Paris commitments, neither backed the EU’s plans for a net zero carbon target by 2050 in their response to an official consultation.

The companies’ decision to withhold support for the target has reignited criticism that major polluters are “greenwashing” their plans for the future while remaining opposed to ambitious climate action.

“You can’t claim to be playing your part in tackling the climate emergency and then refuse to back the legislation we need to succeed,” said John Sauven, the executive director of Greenpeace UK.

“While Big Oil CEOs proclaim their support for climate action, their rigs are still heading out to drill for more oil and their lobbyists are still busy undermining climate action.”

Official documents, compiled by the investigative journalism arm of Greenpeace, Unearthed, show that BP used the consultation to warn against “promoting any one fuel as the answer”, because the world “will need all forms of energy for a long time to come”. It made no reference to a 2050 carbon target.

Shell told Brussels it supports a net zero carbon goal, but shied away from a specific timeline for the emissions cuts. It has previously proposed a global net zero carbon target of 2070, but is understood to be wary about committing to date for an EU target.

A company spokesman said Shell is committed to reducing carbon emissions in line with the Paris agreement but also declined to give a target date for a carbon neutral future.

A spokesman for BP said it supports a carbon neutral future “in the decades to come”.

Utility groups – including Centrica, RWE and E.On – lobbied for the EU to stick with existing plans to reduce emissions by between 80% to 95%, despite concerns that these cuts do not go far enough to limit severe global heating.

A spokesman for Centrica said the energy company’s view “has evolved since our response to the consultation”, which was submitted last September.

“As a result of new evidence being provided to us, we support the view that a net zero emissions target will be a challenging target to meet, but it is the right thing for the UK – and the EU – to aim for.”

The UK became the first major economy to enshrine in law plans to cut carbon emissions to net zero by 2050 earlier this month.

Sauven said: “Centrica’s U-turn in favour of a net zero target shows that at least some companies may have clocked the gravity of the climate emergency we face. It’s time for BP and others to follow suit.”