Because your son was asked to withdraw, he likely failed to meet the minimum academic requirements set by the university. This withdrawal would appear on his academic record.
Reapplying in the UK:
He can reapply to UK universities, but he will need to explain the circumstances of his withdrawal. He will likely need to:
* Address the reasons for his failure: Honesty and a plan to avoid similar issues are crucial. Was it academic difficulties, personal issues, or something else?
* Demonstrate improvement: This might involve further study, gaining relevant work experience, or seeking academic support.
* Apply to different universities or courses: He might find success applying to universities with lower entry requirements or less competitive courses.
Reapplying in the US (Assuming you meant to ask about the US system):
This is impossible without more information. The answer depends on whether you son is a UK or a US citizen. The details of how the withdrawal is recorded also matters. Some US colleges will accept students who withdrew from another college, others may not.
If your son is a UK citizen seeking admission to a US college, he would apply as an international student, which is a more challenging process. He would need to meet the college's admissions requirements for international students. A prior withdrawal from a UK university would need to be explained clearly and honestly in his application.
If he's a US citizen studying in the UK, things might be simpler. However, a withdrawal from a UK university will still need to be explained. Applying to US colleges as a "freshman" after a withdrawal will depend on the individual college's policy. Some colleges may allow this; others may require him to apply as a transfer student.
In short: You need to contact the UK university to fully understand the reasons for the withdrawal and what is recorded on his academic transcript. Then you need to research universities (in the UK or US, depending on your goal) and understand their admission policies and requirements for applicants with prior academic issues. It's best to speak to an admissions advisor at potential universities to discuss his options.