I am switching from outsorcing my payroll to bringing it in-house in the next financial year. What information will I need from my current payroll provider in order to setup my in house payroll system?
If it is April to March, then you will need the PAYE Ref and Accounts Ref numbers, names, addresses, dates of birth, NI numbers and the tax code for the previous year (so that you can work out the new tax code if the HMRC haven't notified you of any new ones).
If halfway through the year, all of the above plus P11 information up to and including the last payroll run by the outsourcer. A copy of the last payslips they produce will be handy too.
Also, check whether they have registered your company under their agency for HMRC online. If they have they will need to de-register you before you can re-register.