In response to Ms Urquhart's allegations, a Suffolk Constabulary spokesman said in a lengthy explanation: 'Police have been carrying out extensive enquiries to locate Corrie McKeague since he was reported as missing on Monday, September 26.
'Throughout the enquiry officers have been investigating the most likely scenario with the information they had at the time, while also carrying out work on other possibilities, with detectives checking and re-checking as is routine in investigations of this nature.
'Initial witness accounts indicated that Corrie may have tried to walk back to Honington.
'There was also speculation that something else may have happened to him that he may have been taken against his will, or had willingly gone with someone else for example - and officers could not afford to rule out any of these options.
'The landfill site search was always one possible line of enquiry police were looking at, after it was thought Corrie's phone may have been in the bin lorry, however it was only one of the possibilities.
'It was thought extremely unlikely that he went with his phone due to the information officers had at that time about the weight of the pick-up.
'Officers were told that the waste pick up from the area was just 11kg, and it was only through a comprehensive and persistent checking process by police that the information that had been provided was recently found to be incorrect.
'The correct bin lorry was seized at the start of the investigation and work was done to see if there was any trace of Corrie within the vehicle or if the vehicle had been involved in a collision.'
She added: 'When an initial decision not to search the landfill was made we remained in contact with the site who had identified where the waste had been deposited.
'They placed nothing further on top of this. Had anything further been deposited we would have encompassed this in the current search.
'Painstaking work was carried out alongside searches, comprehensive CCTV examination and background enquiries to see what may have happened.
'The combination of the lack of CCTV sightings and witness information gradually ruled out many of the other possibilities but it was only by carrying out these enquiries and the work to check the data provided - that this was found to be the most likely option.
'We remain committed to finding out the truth about what happened to Corrie, and work to search the landfill site at Milton in Cambridgeshire continues.'