The three were killed in the bombing of the Shangri-La Hotel, Colombo, on Sunday morning, he said.
Eight British citizens were among the 290 people killed in bomb attacks on hotels and churches in Sri Lanka, the UK's High Commission in Colombo said on Monday.
The victims included Anita Nicholson, her 14-year-old son Alex and her 11-year-old daughter Annabel, her husband Ben Nicholson said in a statement.
The three were killed in the bombing of the Shangri-La Hotel, Colombo, on Sunday morning, he said.
Ben Nicholson, who survived the attack, said Anita was a "wonderful, perfect wife and a brilliant, loving and inspirational mother to our two wonderful children".
"Alex and Annabel were the most amazing, intelligent, talented and thoughtful children and Anita and I were immensely proud of them both and looking forward to seeing them develop into adulthood," he said.
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