Jun 02, 2019
First off, let's save some time. Here are places you can get UK merchant accounts as at 14.10.16:
UK Acquiring Banks
Payment Processors (factoring services)
The basic rule is that you get your own merchant account if you're making more than £1k p.m. through credit-card sales. Intermediaries take a % of your sales and that adds up even if it's only 2% per transaction.
Providers are taking a chance on you, so you can't just sign-up for a merchant account without expecting some background checks: credit-check, company registration, business type, personal ID, etc. If you're dodgy or your clients are dodgy the chargeback rates go up and then your account is closed and the provider gets heat from farther up the credit chain.
Certain business types are classified as high-risk e.g. gambling, and high-street providers won't touch them.
Honest-but-dumb merchants don't help their case by taking orders which look suspicious in the fervent hope that they've made a big sale at last e.g. A guy based in a Third World country getting some UK bod to ship him £5k worth of iPhones on American Express? He's using a stolen card! Refund him immediately and don't listen to any guff.