The National Trust has called for a £5.5 billion commitment from the Government to invest in "greening" the nation's most deprived and greyest urban areas over the next five years.

According to new research, commissioned by the National Trust and partners, more than 20 million Britons stand to benefit from such an investment into green infrastructure - to the tune of an estimated £200 billion in physical and mental health benefits.

The study identified three major interventions to "level up" access to quality green spaces.

These are: transforming grey side streets into street parks, upgrading poor quality parks with more trees and better facilities to make them "fit for the 21st century", and creating large regional parks and forests on the urban fringe to make it easier for people without a car to enjoy wild natural spaces.

The director-general of the National Trust, Hilary McGrady, said the surge in use of green spaces during the coronavirus pandemic - up 25% this May compared to May 2018 - showed a desire for urgent green investment in neighbourhoods, towns and cities right across the country.

She said: "We are calling for a major collaborative effort - for national Government, local councils, charities, businesses, communities and funders across our cities and towns to work together in new ways to bring nature and beautiful green spaces into everyone's lives.

"Everyone needs access to natural beauty for their wellbeing. It's the very foundations on which the Trust was built, and we want to live up to that ambition by supporting partners, projects and innovations that can deliver this humble but inspiring benefit to millions more people.

"Now is the time for Government to be bold and ambitious for the future, investing in the upgrade, extension and connection of the vital green infrastructure of towns and cities, just as it is doing for transport infrastructure," she added.

"The Prime Minister could lead a transformation that enables all urban dwellers to live with beauty; a gift of renewal and hope comparable to the post-war creation of the nation's great rural National Parks and its urban green belts."