Every companies policies are different
If there is no policy on this issue, this is the current UK legal stance:
Time Off for Dependants: If you have a sudden or unexpected problem with your care arrangements you have the right to take a reasonable period of time off work to deal with the emergency or to make any necessary long term arrangements. There is no set limit to the amount of time off but it will usually be limited to 1or 2 days. It does not mean that you may take 2 weeks leave to look after a sick child. Whether the leave is paid is left to the employer's discretion so will depend on your contract of employment. For further information see Parental leave or contact ACAS