The Prime Minister has promised to meet "father to father" with British Army veteran Richard Lee, whose daughter Katrice went missing nearly 40 years ago.
Boris Johnson made the pledge in the House of Commons in response to a question from Mr Lee's MP, Jill Mortimer.
Katrice Lee disappeared on 28 November 1981 – her second birthday – from a NAAFI shopping centre in Schloß Neuhaus near Paderborn in Germany.
The Lee family lived in Schloß Neuhaus, while Katrice's father, Richard Lee, was serving as a sergeant in the 15th/19th King's Royal Hussars in Paderborn.
The two-year-old was born with a condition in her left eye that would have needed two operations to correct.
Ms Mortimer told the House of Commons: "Richard Lee, a constituent of mine and veteran who served with distinction in the British Army, has been living with this pain every day of his life since 28 November 1981."
She asked the Prime Minister to meet with Mr Lee to "reassure him that Katrice has not been forgotten".
Mr Johnson responded on what he called an "absolutely tragic case", stating he would meet with the Army veteran "father to father".
Following the Prime Minister's pledge, Mr Lee tweeted Forces News, saying: "I have been in this position before.
"Until I am sat in his office l will approach this with caution."