Figures for the start of August show that the total number of patients registered with the service has risen to 59,924 and its list size increased by more than 8,000 in the past three months.
GP at Hand now has almost 12 times the number of patients it had when it first launched in November 2017 when the GP practice in Fulham, south-west London that hosts the service had just 4,970 patients.
NHS patients who live or work within 40 minutes of one of the service's five London clinics have been able to register with GP at Hand since November 2017 and since then its list size has grown rapidly.
In June this year, GP at Hand was given the green light to expand to the Birmingham and Solihull area. However it was told it could only recruit up to 2,600 patients from the area during its first three months and that these patients must live within the Birmingham City Council and Solihull Metropolitan Borough Council boundaries.
A review is due to be carried out after eight weeks, which will assess whether these limits could be withdrawn and the service allowed to expand more widely in the region.
The latest NHS Digital statistics do not provide data on where patients live so it is unclear how many of the patients who have signed up to GP at Hand in the past three months are from Birmingham.
Babylon GP at Hand has consistently denied claims that it has 'cherry-picked' younger patients. However, the latest statistics continue to show that the majority of patients registering with the service are younger people.
Some 85% of Babylon GP at Hand's patients are aged between 20 and 39 - the same proportion as were registered in May, the last time GPonline undertook this analysis.
The number of patients aged between 20 and 29 registered with the service is 30,676 - over half (51%) of its total list. In comparison, just 13% of the registered patient population across England is aged between 20 and 29.
Meanwhile only 1% of GP at Hand's patients are aged 60 or over, compared with 23% of all patients registered at practices in England.
Because so many 'out of area' patients have signed up to the service Hammersmith and Fulham CCG has been left facing soaring costs and a growing deficit. Earlier this year, NHS England confirmed that it would cover the full costs the CCG would incur as a result of GP at Hand in 2019/20 - estimated at £21.6m.
A major independent report commissioned by Hammersmith and Fulham CCG, that was published this year, found that the service may be unsustainable if rolled out across a wider population.
It also found that GP at Hand had attracted predominantly young, wealthy patients who use NHS services with above-average frequency despite being healthier than the average for their age.