Litvinenko, a former colonel in the Russian secret service, was a fierce critic of the Kremlin
Reid said he was confident London was getting the necessary assistance from Moscow over what happened to the former Russian spy.
But as the police probe into Litvinenko's mysterious radiation poisoning entered its third week, reports said Britain feared a long-term diplomatic fall-out with Russia from the affair.
Reid, who was to meet European counterparts in Brussels over Monday and Tuesday, vowed that all information would be followed up wherever it lead.
"Over the next few days, I think all of these things will widen out a little from the circle just being here in Britain" John Reid, the British Home Secretary Send us your views"Over the next few days, I think all of these things will widen out a little from the circle just being here in Britain," he told Sky News television.
"Over the next few days, I think all of these things will widen out a little from the circle just being here in Britain"
John Reid, the British Home Secretary
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Poisoned contact
Italian academic Mario Scaramella, the contact of Litvinenko who tested positive for the radioactive isotope polonium-210 which poisoned the former agent, was said to be "well" in hospital.
Self-styled security expert Scaramella met Litvinenko in a London sushi restaurant on November 1, shortly before the former spy first felt ill.
The Italian "remains well, the results of his pathology tests to date remain normal," said a spokesman for University College Hospital, where Litvinenko died on November 23.
The former Russian agent wrote a letter on his death-bed which pointed the finger directly at Vladimir Putin, the Russian president, whom he described as "barbaric and ruthless".