Wide as the Clyde 

The Clyde is a massive river in Glasgow. The insult is a response to someone who done something cruel, wrong, cheeky, or cheeky. The insult is often made in response to a wise cracker or a joke merchant who done or made fun of someone's expense. It's banter to say this to your friend as a joke when they piss you off or when they make a joke that's sick or funny at your expense. Also when some one doesn't give you what you want you could say this.

You're as wide as the Clyde. He's/she's wide as the Clyde.

Wide as the Clyde by Ker Ber March 15, 2018

As wide as the Clyde 

The Clyde refers to a river in south Scotland that flows northwest.
The term ‘as wide as the Clyde’ likely denotes the length or size of the object or idea referred to (i.e. it can refer to figurative or actual lengths and distances).

Alison Thewliss (SNP frontbencher)
...the NAO report blows a hole ‘as wide as the Clyde’ through everything the Tories have been saying on Universal Credit.

As wide as the Clyde by Irtiza July 5, 2018