The CBI helps create and sustain the conditions in which businesses in the UK can compete and prosper for the benefit of all.

They are the premier lobbying organisation for UK business on national and international issues. The CBI works with the UK government, international legislators and policy-makers to help UK businesses compete effectively.

Employers section of the HMRC website with information about registering, PAYE, NI, etc.
Useful info for SMEs regarding redundancy, employment tribunals and discipline.