Manchester United star and England captain was speaking during a video call convened by the Duke of Cambridge who has launched a declaration to create a "mentally healthy culture" in the sport.
It has been signed by governing bodies, leagues and organisations from across UK football.These organisations will form a UK-wide mental health implementation group next season, working towards a collective "game plan" to prioritise the psychological wellbeing of everyone involved with football.
And David says it's only now, looking back, that getting sent off during a World Cup match against Argentina in 1998 - when he was just 23 - was the most difficult time in his footballing career.
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