Do you have any existing contacts who can help you find an internship in the UK?
They may have some employer contacts in the UK. If you are doing a vocational degree, for example, in engineering, your department may also have links with certain employers.
Many companies have offices or links with companies overseas. If you have worked or done an internship in your home country it may be worth approaching them again to see if they have any suggestions of who to approach in the UK.