Regulators have promised to make it easier for people with cancer and other serious medical conditions to buy travel insurance, but campaigners say the proposed changes do not go far enough.
For the past year, the UK's Financial Conduct Authority has been looking into the problems that people with medical conditions have in finding cover.
In one response to the regulator's official call for input, a person with "low grade bladder cancer" needing no regular treatment — and only six-monthly check-ups — was charged £450 for a travel insurance policy for a six-day trip to America.
The FCA said it would introduce a signposting system so that people who cannot get insurance with mainstream insurers — or are provided with very expensive quotes — can be directed towards specialist providers.
Campaigners said the FCA could have done more to help people who are priced out of travel insurance.
Macmillan's research suggests that people with cancer pay nearly four times the average cost of an annual travel policy for the general public.
He said that it was important for people with cancer to understand how insurers would price their policies, so they could make an informed decision about which insurance company to choose.
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