The Fundraising Regulator and the Charity Commission have jointly produced some guidance for people who are thinking about fundraising for charity, including in response to an emergency.
They say that the guidance explains what people should consider before setting up an appeal, including choosing a charity to fundraise for, being clear with donors about how donations will be used, using reputable fundraising platforms where possible, and making contingency plans if funds cannot be used as intended. It also includes advice on fundraising in response to an emergency and fundraising for a personal cause.
You can read their guidance at https://www.fundraisingregulator.org.uk/about-fundraising/resources/setting-general-or-emergency-fundraising-appeal-advice-public.