Employees may be eligible for Statutory Paternity Leave and Pay if they and their partner are:

• having a baby
• adopting a child
• having a baby through a surrogacy arrangement

Employees can choose to take either 1 week or 2 consecutive weeks’ leave. The amount of time is the same even if they have more than one child (for example twins).

Leave cannot start before the birth. The start date must be one of the following:

• the actual date of birth
• an agreed number of days after the birth
• an agreed number of days after the expected week of childbirth

Leave must finish within 56 days of the birth (or due date if the baby is early). The start and end dates are different if the employee is adopting.

https://www.gov.uk/employers-paternity-pay-leave