Those who are asked to lead worship on behalf of others are undertaking an important responsibility.
Clergy and Readers are licensed by the Bishop to lead worship.
Churchwardens may also lead worship.
Many churches now have groups of worship leaders who prepare and lead non-eucharistic worship.
Here are a worship resource sheet (PDF) and some orders of service that churchwardens can use if they need to lead an act of worship at short notice. The orders of service are Word docs so they can be adapted if needed.