An 89th-minute penalty sent Hayes and Yeading tumbling out of Conference South after a dramatic final day ended in heartbreak.
Phil Babb’s men came within minutes of survival as they were holding play-off chasing Dover 1-1 in the club’s final game sharing at Woking’s Kingfield Stadium.
Geoff Mitchell had cancelled out Nathan Elder’s early goal and at half-time results were going their way, with Whitehawk losing 3-2 at home to Sutton.
United lost keeper Charlie Crowley at half-time, with goalkeeping coach Delroy Preddie replacing him, and nerves began to jangle when Whitehawk equalised.
With goal difference in their favour, United only had to match Whitehawk’s result – but as time ticked down, Dover were given a penalty for handball.
Former Millwall midfielder Barry Cogan tucked the ball away to confirm Hayes and Yeading’s relegation.
It will come as a huge blow for United, who were sixth in December after beating Tonbridge 3-0.
But they picked up just two points from the next 11 games and in spite of three wins in April, it was not enough to keep them up.
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