14/04/2016 12:10 BST | Updated 15/04/2017 06:12 BST

Parkrun Is a Globally Successful Initiative - That's Why We Have to Fight to Keep It Free

A Bristol parish council's move to charge participants of a weekly running event is the latest decision to erode the principle that our parks are free. The organisers of the timed Parkrun in Little Stokes Park, who've set up a petition on, have said that it will mark the end of the community event. But it's not the first time a group like this have come under threat from parks introducing fees.

Three years ago I had the toughest softball season that I've ever faced. But the challenge didn't come from any of the dozens of teams that make up the London Charity Softball League. Instead my fight would be against the Royal Parks themselves, in 18 month battle involving legal action to remove charges from Hyde Park and keep it free for the public to play sport.

The argument at the centre of both cases seems to be that because groups are using an area, they should be asked to pay. Which might sound reasonable until you realise we already have paid, it's what some of our tax goes towards.

Parks are a vital part of our community and they are there to be used. Barely a week goes by without a story about the need to tackle the increasing rates of obesity in the UK, with the WHO reporting in 2014 that more than 28% of adults in the UK where clinically obese. Even the health secretary, Jeremy Hunt, earlier this year described rising childhood obesity rates in the UK as a 'national emergency'.

So anything that's successfully getting people out of bed every weekend to be a bit more active should be encouraged and celebrated. And it's not just our physical health that is improved when we get outside, there's numerous studies linking exercise to better mental health. It also enables people to meet others and get involved in their community. Issues councils are spending money on elsewhere desperately trying to tackle.

Parkrun is a globally successful initiative which has got millions of people around the world regularly running 5K. What makes it work is it's ethos of being free and open to everyone. Each one is set up within a community, staffed by local volunteers who get up early every Saturday to make it possible for others to take part.

However the growing trend seems to be, if you create something that is successful and popular, others see it as a justification to charge for it. A senior member of the Royal Parks even once told me in a meeting that, people often don't really appreciate something unless they pay for it. It was a point they soon backed down on when challenged.

But even a small charge creates a barrier to people taking part, and once the principle has been established it'll be difficult stop it increasing in future. Not only that, it discourages anyone from creating similar schemes as the costs will stop them as soon as it becomes successful.

Ultimately this is an issue that is going to continue and no doubt be replicated up and down the country as councils look for ways to stretch their limited budgets further. I was lucky that due to the overwhelming public support for our own petition, and some brilliant lawyers from Leigh Day, we were able to challenge the Government to get the Royal Parks to remove the fees in Hyde Park. But if we want to stop what's happened in Little Stokes Park happening to others and make sure our parks remain free for everyone to use, we're going to need to stand up and fight for them.