The UK does not have the "right policies" to meet legal renewable energy targets, Energy and Climate Change Secretary Amber Rudd has admitted.

But appearing before a parliamentary committee after a leaked letter emerged spelling out an expected shortfall in the target to source 15% of the country's energy from renewables by 2020, Ms Rudd insisted she was committed to achieving the goal.

The letter from Ms Rudd to colleagues, leaked to the Ecologist magazine, disclosed the UK is set to fall short of its legally-binding European Union target for energy for transport, power and heating, achieving only 11.5% from renewables, rather than 15%.

The letter suggested ways of meeting it by buying hydropower from Norway, purchasing clean energy from other EU states, doing a deal with a European country which has over-achieved on its targets to buy their "credits", or even negotiating for flexibility in the goal.

It prompted an angry response from green campaigners, who claimed it pointed to an "incoherent" energy policy by the Government, which has cut subsidies to renewable technologies such as onshore wind and solar in recent months.

To meet the overall 15% goal, the UK aims to source 30% of its electricity,10% of transport energy from renewables and 12% of heating from renewables by 2020.

Ms Rudd told the Energy and Climate Change Committee that the UK was on target to meet the goal of 30% power from renewables, but she said she was "concerned" about the situation for renewable heating and transport.

She told MPs on the committee: "It's my aim we should meet the 2020 target. I recognise we don't have the right policies, particularly in transport and heat, but we have four to five years and I remain committed to making the target.

"Currently there's insufficient evidence we're going to make the 2020 target unless we take certain action, I remain committed to taking action to meet the target."

Questioned on whether moves to curb support for renewable power were wrong in light of the disclosures, Ms Rudd insisted it was better to tackle the problems in heat and transport rather than step up deployment of green electricity.

"I think it would be a mistake to abandon heat and transport. They are part of the mix for a good reason.

"I would much rather address the issue of heat and transport than just say let's step up electricity. It's not the answer to do more electricity."

And she said she was clear the Government required policies on renewables to provide value for money.

The renewables sector has criticised ministers for cutting subsidies to the cheapest green technologies such as onshore wind, and supporting more expensive offshore wind and nuclear.

Green MP Caroline Lucas said:"This Government's credibility on climate change is lying in tatters.

"To create jobs and tackle climate change, the UK should be leading the way on clean home-grown energy. Ministers must get a grip and urgently act to ensure we meet all of our renewable energy targets."

Environmental group Friends of the Earth warned it may launch a legal challenge against the Government if it fails to put in place a credible plan for meeting its 2020 renewables targets,

Energy campaigner Alasdair Cameron said: "Without serious additional action the UK is on course to miss its legally binding renewable energy targets for 2020 - and recently proposed cuts to support for wind and solar technologies will make matters worse."

He added: "Renewable energy is the future - the Government must get on board and help build the low carbon, affordable economy we so urgently need."