Mr Hancock, whose West Suffolk constituency includes Newmarket racecourse, told the Commons that horse racing was the Queen’s “greatest love outside her duty”.
Speaking about the Queen’s visits to Newmarket, Mr Hancock said: “The first time I met her I was lucky to be with my small daughter who handed her a posy, and it is my daughter’s first memory and no doubt will be an abiding one for the rest of her life.”
He added: “The one thing we do know is that the reason that Her Majesty loved to come to Newmarket was not because of us two-legged beings, but because of the four-legged beings.
“Her love of horse-racing was perhaps her greatest love outside her duty to her family and her country.”
On the Queen’s connection with horses, Mr Hancock said: “The twinkle that we have heard so much of, and the genuine smile that came on her face was probably broadest when at a racecourse, as she demonstrated in what was probably her last social public occasion at Ascot.
“I remember it particularly at a visit when she came to open the National Horse Racing Museum, which is in Newmarket.
Her love of horses from thoroughbreds to native ponies shone through. You see it in those sparkling smiles
Plaid Cymru Westminster leader Liz Saville Roberts
“She went down the line of dignitaries, she went down and met the public, she gave them her customary focus, but she was clearly doing her duty because the museum is full of retired racehorses, and it was only when she got to the horses that she really lit up.
“This was Her Majesty at her best. We have lost a great servant.”
Plaid Cymru Westminster leader Liz Saville Roberts also recalled the Queen’s love of horses.
She told the Commons: “Her love of horses from thoroughbreds to native ponies shone through. You see it in those sparkling smiles.
“Everyone in public life knows you have a public smile, but the photos with the horses, that was her real smile.”
Ms Saville Roberts also said the Queen was a “magnificent role model for older women”, adding: “Historically of course, older women have disappeared from public life. The Queen was a constant visible figure throughout the 70 years of her reign.”
Recollections of the Queen’s love of horse racing come as several sporting events have been cancelled.
Racing at Southwell and Chelmsford on Thursday evening was abandoned.
The British Horseracing Authority also announced the meetings scheduled for Friday – including the third day of the St Leger meeting at Doncaster – were cancelled.