Employers must to provide you with the fine print within two months of your start date:
https://www.gov.uk/employment-contracts-and-conditions/writt...
Any incontrovertible evidence of an agreement of the job, verbal or written, counts as a contract. Everything else is just finalizing the terms and conditions, which either party can agree to amend at any later date and which many employers assert they can do unilaterally.
P.S. Not doubting your experience, just comparing it with mine.
Is this common in the USA? In the UK I've never been offered or heard of anyone receiving a bonus for signing a contract. Does anyone have a different experience?
It 100% doesn't matter either way, as those bonuses always come with attrition requirements - you have to pay back all or part the bonus if you leave the company before some predetermined time period. If you don't agree to the payback terms then you simply don't get the bonus.
So a bonus paid before you start is more-or-less identical to a bonus paid with your first paycheck. You don't get to keep it if your offer is rescinded or you don't show up on your first day.
I've seen them be offered in jobs/industries/companies where there is a labor shortage or the job is difficult to fill for some reason. They might be standard-ish in some jobs/industries.
like I said, you'd almost always be required to stay for X amount of time - like a year plus usually, or you gotta pay some or all of it back.
I should have persisted and ghosted them, they ended up putting me in a different role than I had been offered and generally were extremely disorganized.
Honestly, I think going forward if you don't have me sign a contract and give me something in return (say, a signing bonus that is actually paid upon signing instead of weeks after I start), the deal isn't done until I start.
When you can't expect the other party to hold up to their side of the bargain because there are bad actors out there, it doesn't make sense to trust them or tell them what's going on until after everything is settled... and even then when litigation is such a concern...