The director for the Coalition for Marriage has handed a petition to Downing Street against plans to change laws to allow gay marriage.
Colin Hart told press outside No 10 that "the government should listen to the people" and to keep existing marriage legislation.
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The four people killed in Wednesday's terrorist attack in London have been honoured by silences across the country.
Man of 58 is still being questioned as police announce that a man of 27 has been released without charge.
Wonderfully sunny weekend