The disease was first diagnosed in 2017, but Kelly's treatment was paused for 12 weeks at the start of lockdown.

Her father, Craig Russell, said the family could not understand why her life prolonging treatment was stopped.

Mr Russell said: "Kelly was devastated as we all were by this because yes, it was a risk. She could catch COVID, but there was no risk she was going to catch cancer.

"She had it and the chemotherapy was the only thing that was keeping her alive. And so yeah, it was very hard to understand the rationale behind that decision."

'We need a new national war on cancer'

The impact of the coronavirus pandemic on cancer treatment has been devastating.

Thousands of early diagnoses have been missed.

Now, Health Secretary Sajid Javid has launched an ambitious 10-year plan that aims to drastically improve people's chances of surviving against this killer disease.

Speaking at the NHS's second proton beam therapy centre at University College Hospital in London, he said: "I want to thank NHS staff up and down the country for how they tirelessly worked on cancer throughout the pandemic.

"But sadly we've seen I think around 50,000 fewer people diagnosed with cancer because of the pandemic, and we do need to go a lot further, a lot faster. We need a new national war on cancer."

"That's why today on World Cancer Day," Mr Javid added, "I'm launching a new call for evidence that will be part of a new 10-year plan on cancer about how we can do even better at prevention, how we can do much better in early diagnosis, and how we can make the very best use of cutting edge treatment."

Read more: Pioneering proton beam treatment gives Teddy back his future

'COVID made things much worse'

The pandemic has certainly made things much worse, but even before COVID, cancer experts had been sounding warnings about the country's poor survival rates compared to the rest of Europe.

Mr Javid said he will collect evidence for his 10-year cancer plan, but health specialists say they have been supplying the government with this information for years.

Oliver Reichhardt, chief executive of the Royal College of Radiologists, welcomed the government's new strategy but warned tackling cancer would take long-term investment.

Mr Reichardt told Sky News: "We have nearly one in five vacancies in cancer doctors, in the diagnosis, the radiologists that look at the images and diagnose cancer, there is a 33% shortfall."

He also said: "We also need investment in equipment: one in 10 pieces of equipment is over 10 years old in the cancer area and while we have great proton beam therapy which is fantastic, we also need to ensure that all the equipment is the latest technology."

The health secretary's 10-year cancer plan will look to learn lessons from the pandemic.

Kelly Smith's grieving family know exactly how painful these lessons can be.