The UK can achieve a "net zero" emissions target and boost the economy at the same time, Prime Minister Theresa May has said.

Mrs May said there was a "moral duty" to leave the world in a better condition than "we inherited" after announcing plans for a legally binding target to end the UK's contribution to climate change by 2050.

The Government is laying out legislation in Parliament on Wednesday to set a new target to cut emissions to "net zero" by the middle of the century.

The statutory instrument will amend the existing goal to cut climate pollution by 80% by 2050, which was agreed by MPs under the Climate Change Act in 2008.

Speaking at Imperial College London, Mrs May said it will make the UK the first major economy to put this "ambitious target" into law.

She added: "I believe we have a moral duty to leave this world in a better condition than we inherited and that's why today we are announcing that we will be ending our contribution to climate change by 2050 and legislating for a net-zero emissions target.

"This will put us on track to be the first major economy to put this commitment into law.

"This is an ambitious target, but it's one that it's crucial for us to achieve and it will take us working across the whole breadth of society to do that."

Mrs May also insisted that lower emissions could be achieved at the same time as economic growth.

She said: "Crucially as we look ahead to meeting this target some people think you can either have low emissions or economic growth - that's not the case.

"Actually what we have shown already is you can lower emissions, and we have this net-zero target, and have economic growth at the same time."

The announcement comes after the Government's advisory Committee on Climate Change called for the new legal target to be brought in as soon as possible and to urgently ramp up action to cut emissions.

Hitting net zero - a 100% cut in emissions - will mean an end to the heating of homes with traditional gas boilers, more green electricity, and a switch from petrol and diesel cars to electric vehicles, walking and cycling.

It could require people to eat less meat and dairy and take fewer flights.

Any remaining pollution in 2050 from areas including aviation will need to be "offset" through measures to cut carbon such as planting trees.

The committee told the Government the move would be in line with commitments to limit global temperature rises to 1.5C above pre-industrial levels under the international Paris Agreement, and will provide leadership for other countries on tackling climate change.

A leaked letter last week showed the Treasury warning the PM that making the shift to a zero carbon economy would cost at least £1 trillion.

But the committee said it will cost around 1-2% of annual economic output up to 2050 - the same as predicted a decade ago for the 80% target - while the cost of inaction would be many times higher.

The shift, which is achievable with known technologies, will deliver economic opportunities and other benefits, the committee said.

In the wake of the committee's recommendations, scientists, campaigners and health professionals have been urging the Prime Minister to bring in a net zero target before she stands down, as a legacy of her premiership.

Number 10 said the move would boost public health, air quality and nature and will make the UK a leader on climate action, as the first G7 group of major economies to put a net zero target into law.

But it was "imperative" other countries follow suit, so there will be a review within five years to ensure other nations are taking similarly ambitious action, and that British industries are not facing unfair competition.

In the wake of widespread climate strikes by schoolchildren and students, the Government is also setting up a Youth Steering Group for young people to advise it on priorities for environmental action.

The Government said it would retain the ability to use international carbon credits, which allow the UK to pay to offset its emissions elsewhere in the world.

Committee on Climate Change chairman Lord Deben said he was delighted the Government was putting the net zero target to a parliamentary vote and was looking forward to cross-party consensus on the issue.

He added: "This step will send a strong signal to other countries to follow suit - and will help to drive the global effort to tackle climate change required by the Paris Agreement.

"This is just the first step. The target must now be reinforced by credible UK policies, across government, inspiring a strong response from business, industry and society as a whole."

Lord Deben also said the Government had not yet formally included international aviation and shipping in the targets, but had acknowledged they needed to be part of the strategy.

Shadow energy secretary Rebecca Long Bailey said: "While this announcement is welcome in theory, in practice it comes from a Conservative government that is off track to meet existing climate targets, that has no plans for legislation or investment needed to cut emissions, and that has dismantled the UK renewable energy sector while pushing fracking."

Dame Carolyn Fairbairn, director-general of business group the CBI, said UK companies were "squarely behind" the commitment.

She said: "This legislation is the right response to the global climate crisis, and firms are ready to play their part in combating it."

Gareth Redmond King, head of climate change at the environmental charity WWF, said the announcement was a "crucial first step".