Large type of bricks covering major city (5,8)

I believe the answer is:

block capitals

'large type' is the definition.
(large text)

'bricks covering major city' is the wordplay.
'bricks' becomes 'blocks' (building blocks).
'covering' indicates putting letters inside.
'major city' becomes 'capital' (I've seen this before).
'blocks' going around 'capital' is 'BLOCK CAPITALS'.

'of' acts as a link.

(Another definition for block capitals that I've seen is " Upper case letters".)

I've seen this clue in The Telegraph.

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