The pair from the Sisters of Charity of St Paul in Moor Drive joined nearly 300 religious from across the country who descended on the Houses of Parliament holding placards and banners calling on MPs to 'Kick the Carbon Habit' and 'Stop Climate Chaos'.

The nuns then met their MP, Greg Mulholland, and discussed the urgent changes that are needed to the Climate Change Bill.

People living in developing countries are the first to experience the devastating impacts of climate change – despite contributing to it the least. Some 150,000 people die each year from the effects of climate change and almost all live in developing countries.

Catholic aid agency CAFOD - which has seen first-hand the effect climate change is already having on the world's poorest communities - organised the lobby along with the Conference of Religious (CoR) and the Justice, Peace and Integrity of Creation Links (JPIC).

They are calling on MPs to strengthen the Climate Change Bill by increasing the carbon emissions reduction target from at least 60% to at least 80% by 2050 and including the UK's share of emissions from international aviation and shipping in the reduction.

One of the nuns from Leeds who took part in Wednesday's event was Catherine Houlihan.

She said: "I come from a generation where waste was sinful. I still feel like that today. I am appalled at the profligate way resources are being wasted. I feel it's important that people are made aware of what is causing climate change."

Her companion Mary Bernard-Potter added: "I have a passion for justice - for people and for our planet. When I was younger my world was very small, over the years I've become more aware of inequality especially in resources.

"It's great to be part of a wider group, we are in a stronger place to influence MPs. Change is all around us but it starts at the grassroots."

The MP for Leeds North West, Greg Mulholland, said: "Face-to-face lobbying is parliament as it should be, there is nothing more powerful in representing people's views."

CAFOD director, Chris Bain, said: "Tackling climate change is essential if the Government's good work in fighting poverty is not to be undermined by rising global temperatures which hit the world's poor hardest.

"We desperately need to see a strong Bill going through Parliament, which shows the UK is taking tough action on climate change, and gives the Government a mandate to speak out at crucial international talks."