Depends entirely on what firm and what jurisdiction. Common associate pipelines to UK firms are Australia, NZ, Canada, Greece, US, Italy, Singapore and Hong Kong. Get a role in a good firm in one of those countries and your chances are pretty good, as long as you're a good lawyer. If you're already qualified, being admitted as a solicitor in the UK isn't
too hard. I don't think the lateral associate market is as competitive as the Disgruntled SQE Student suggests - firms need lots of associates to bill clients, and associate attrition is quite high in general.
Obviously, it's not a walk in the park. Lots of people want to make the move, so there is competition for the best spots.
The biggest problem is that you need to fit the kind of skills and experience the UK firms are looking for. Being a property lawyer or pensions lawyer in a foreign jurisdiction isn't very useful. I would say the following foreign qualified lawyers are quite sought after:
- US-qualified finance lawyers. There's a ton of American, Greek and Italian lawyers in the UK who specialise in high yield bonds.
- Projects and project finance lawyers. Soooo many Australians. Very little actual law involved. Deals are all international.
- Arbitration and PIL lawyers. Goes without saying.
- EU / Competition lawyers. Can qualify in any EU jurisdiction then make the switch. Lots of UK competition partners go between London and Brussels.
Bonus points if you do a UK LLM in one of these fields after having qualified abroad.
Regarding having been rejected for TC, I second
@Disgruntled SQE Student 's answer. It is not going to make a difference.