The first item of business in all four Houses covered by this blog (UK - Commons; Lords US - Representatives; Senate)is prayers. The main difference being that whilst in the USA the public can see prayers (and the prayers may include them) - in the UK prayers are held in private. No one is allowed into the visitors galleries until prayers are finished.
It is believed that prayers at the start of Commons' business dates back to about 1558.
In the Commons the Speaker's Chaplain usually reads the prayers. The form of the main prayer is as follows:
"Lord, the God of righteousness and truth, grant to our Queen and her government, to Members of Parliament and all in positions of responsibility, the guidance of your Spirit. May they never lead the nation wrongly through love of power, desire to please, or unworthy ideals but laying aside all private interests and prejudices keep in mind their responsibility to seek to improve the condition of all mankind; so may your kingdom come and your name be hallowed.
Amen."
The prayers in the Lords are led by one of the 26 bishops who sit in the House. (if all are unable to attend there are a number of ordained ministers who could substitute). The prayers which are used are listed here.
Both houses of Congress have their own chaplains - though guest chaplains may be invited.
In a recent interview the Senate Chaplain discussed his role (which caused some controversy because, unlike in the UK, there should be separation of Church & State)