You can look on Companies House although for small companies the information they need to publish these days is restricted, for example they may well not have a profit & loss account included, just a balance sheet, so you only get a feel for the assets of the company rather than the revenue stream. Remember that the accounts for a private company, at least, can be filed up to nine months after the financial year end so can be quite out of date. You can also get reports from credit reference agencies but again the information will be restricted where the company is small. Companies can now also file "filleted accounts" at Companies House instead of the full accounts that the shareholders are entitled to and this further restricts the information available.