A p35 is a year end return showing who you employed as an employee during the tax year 2011 (from the 1st of January to the 31st of December). It shows who was employed, their tax number, the USC, PAYE and other taxes deducted. Think of it as a breakdown of your employee payroll for the year.
You have to file your 2011 return with Revenue by the 15th of February 2012 or you risk fines which go up to €4,000 and you may face an audit as well. If you submit online via ROS (Revenue Online Service). There are charges due for underpayment, if your underpayments to date are greater than 10% of the years liability then you get charged a surcharge. If the difference is less than that you pay the difference.
RCT or ‘relevant contract tax’ is a tax deduction (usually from principle contractors to subcontractors – you see this often in construction) of 20% (it used to be 35%) and the deadline for this is the same as for the P35.