Selhurst Park hosts Brighton this Saturday in the 99th instalment of the derby, but it may not be the most obvious of rivalries.

Geographically they are not close as most derbies tend to be, nor is it an age old rivalry.

So where did the bitter feud in what is now called 'The M23 Derby' come from?

It seems it's a feud that began as recently as 1976, and it came about via their managers.

Terry Venables and his former Tottenham team mate Alan Mullery were named managers of the Eagles and the Dolphins (as they were called then) respectively that summer.

It was said the two were ‘enemies’ after the Spurs manager, Bill Nicholson, overlooked Venables in favour of Mullery for the captaincy during their playing days.

A rumour Mullery denied.

“It was a friendly rivalry — we've never been enemies,” Mullery told the Guardian in 2011.

“We used to share a room together at Tottenham and I still bump into him occasionally."

Your Local Guardian:

(Mullery during his Brighton managerial days)

READ: Huddersfield manager has his say on 'bust-up' with Palace loanee

Magic of the FA Cup

Both sides that year were going for promotion from the third division, and would end up playing each other five times that season, but the match that many feel sparked the birth of the rivalry was the FA Cup first round replay which was held at Stamford Bridge after drawing twice previously.

Palace took the lead through Paul Holder in the first half but Brighton should’ve been level soon after but Peter Ward’s effort was incorrectly chalked off for hand-ball.

If Brighton felt aggrieved by that decision, imagine the rage they’d feel in the second half when Brian Horton’s converted penalty was asked to be re-taken after encroachment……by Palace players.

Needless to say, the re-take was saved and the tie ended 1-0 to Palace.

Your Local Guardian:

'That's all you're worth, Crystal Palace'

It was Mullery’s actions at full-time many feel spawned the what is now the bitter rivalry.

"I was angry but it wasn't because we'd lost," said Mullery.

"It was because of the referee's decision to force us to retake the penalty.

“After the game I approached him and asked him why he had made that decision.

“He said it was because of encroachment, but it was Crystal Palace players who were encroaching, not Brighton players.

“It was a terrible decision."

"As I was walking up the tunnel a load of boiling hot coffee was thrown over me by a Crystal Palace supporter.

“So I pulled a handful of change out of my pocket, threw it on the floor and shouted, 'That's all you're worth, Crystal Palace!' And I'd shout it at anybody who did that."

The manager was led away by police and fined for bringing the game in to disrepute, but the damage was done.

A rivalry was born.

That season both teams were promoted.

Mullery, as Palace fans know, went on to manage the Eagles later in his career.

He said of the rivalry:

“I used to find it very difficult to understand what their problem was.

“Portsmouth and Brighton are 20 miles apart, Arsenal and Tottenham are about three miles apart.

“When you've got clubs 45 miles apart it does sound a bit silly."

READ:Crystal Palace's Vicente Guaita puts transfer rumours to bed

READ: Brighton's Chris Hughton dealt injury blow ahead of Palace clash