You are entitled to claim holidays that you have accrued over the course of your holiday year up to the point of your redundancy, but not taken. You are also entitled to claim for holidays you have taken but not been paid.
Holiday pay is limited to 6 weeks of holiday pay due in the last 12 months, at the statutory limit of £700 per week. Income tax and national insurance at the basic rate are deducted from this amount.
Example
You worked 5 days a week and earned £430. Your holiday year was from 1 January to 31 December and you were entitled to 30 days' holiday leave in the holiday year. Your employment ended on 30 June halfway through the holiday year; so you were entitled to 15 days' holiday when your job ended. You had taken 1 weeks' holiday (5 days) leaving 2 weeks' (10 days') unpaid holiday entitlement. The government would pay you 2 weeks' holiday pay at £430, the statutory rate of pay, which comes to £860 [2 x £430 = £860].