Ross and Clare Simons had been married for about 18-months when they were killed after a man knocked them off their tandem bike in January in Bristol.
Nicholas Lovell, 38, will be sentenced in four weeks after pleading guilty to causing the deaths by dangerous driving of the couple.
Mr Lovell's partner Louise Cox has pleaded guilty to perverting the course of justice.
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The Office for National Statistics said gross domestic product grew by just 0.1%.
William's comments came during a surprise appearance at an event scheduled for just his brother.
Matt Campbell, who collapsed just a few miles from the finish line, had hoped to raise £2,500.