The man was arrested in Ipswich this morning.
The Serious Organised Crime Agency says it is the first arrest as part of Operation Pallial, which last November started investigating recent allegations relating to historic child abuse in North Wales.
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The peer will attack Prime Minister Theresa May for failing to represent the 48% who voted in favour of Remain.
Paul Flynn, MP for Newport West, will open the debate in Westminster Hall.
It will represent another boost to the region, after the announcement Deca Sealand was chosen for a repair hub for defence aircraft.