Her comments come as the gates of her local Brockwell Park were "slammed shut" last weekend due to overcrowding.
Aside from shopping for essential items, Brits are only allowed outside for one hour of daily exercise each day.
However, sun seekers in their droves were pictured sunbathing in the park, forcing the council to close its gates.
Some were even seen socialising in groups – a strict breach of the lockdown guidelines.
Speaking in her Daily Mail column, Susanna revealed her anger – both at the closure and the selfish stupidity of the 3,000 people who descended on the park.
All park-goers were punished for the actions of the few who thought the rules didn’t apply to them.
Susanna said: "On Sunday, all park-goers were punished for the actions of the few who thought the rules didn’t apply to them, as the council decreed it couldn’t cope with the numbers and the gates were shut."
"Vital breathing space"
She added that the park is a "vital breathing space" in an area where many young families live in small flats without access to green space.
Susanna has also pleaded with health secretary Matt Hancock to keep the country's parks open.
Her comments came after he threatened to take away the "precious" daily exercise allowance if Brits continue to flout the rules.
Susanna said: "If you felt claustrophobic when he said that, you weren’t alone. A daily walk is the silver lining of what feels at times like a very dark cloud. So this is my plea to the government — national and local — to keep our parks and green spaces open."
The GMB host even went so far as to say a trip to the park isn't a "luxury", it's essential.
Police need to be patrolling coastlines and the big parks . On the spot fines with monies donated to the NHS. I am a running coach so I am outdoors all the time usually. Exercise CANNOT be banned. Mental health will be the biggest cost to the NHS because of #COVIDー19
— Samantha (@Moz0373Runner) April 9, 2020
The smart move over the bank holiday weekend is to shut the parks, remove the temptation..
— Ben Ramsey (@BenRamsey2) April 9, 2020
"Lockdown is bearable if we know we can glimpse the outside world occasionally. Seeing trees, a big expanse of sky, walking on grass. Getting out isn’t a luxury — it’s a necessity," she said.
The star said she stayed at home as the sun shone last weekend.
Stay home, stay safe
However, she admits that she knows she's lucky.
She said sitting outside in her garden, hanging her washing on the line and exercising with her hula hoop keeps her "fit and sane".
With sunshine predicted across Easter weekend, Brits are urged to stay home and stay safe.
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