The Paddington Arm of the Grand Junction Canal opened on 10 July 1801, linking Paddington to the Bull's Bridge junction near the future site of Heathrow Airport. The Grand Junction (now part of the Grand Union Canal) was the final link in a chain of canals that reduced the distance from London to Birmingham from in 1789 to in 1805; terminating the canal at Paddington gave easy access to main roads into London and the level route meant no locks were needed on its length. In contrast the Regent's Canal needed 12 locks for the descent from Paddington to the Thames at Limehouse.