Seal colony in Thames Estuary
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Scientists find 'incredible' seal numbers in London

Conservationists who have been counting seals in the Thames Estuary say the numbers they have found are "pretty incredible.''

In the first survey of its kind, volunteers spotted more than 700 grey and harbour seals living in London's famous waterway.

The pioneering work was carried out by the Zoological Society of London.

Jane Hill reports.

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