This is consistant with the report from the Parliamentary committee which highlighted the lack of a information about an MoD budget for purchases beyond the first 48. Probably because there isn't one being penciled in for their long term planning.
The long term planning is simply not long term enough. There is supposed to be an SDSR every 5 years, while equipment spending is planned out on a 10 years period.
The last major projects spreadsheet to come out had the F-35 programme end date as 2035, which suggests they are planning to spread the purchases over
at least that many years. The budget associated with the date is billions higher than the 9.1 billion for the first phase and the 48 on order. Moreover, these spreadsheets change year on year: for example, the previous year variant had the end date as 2026 (given as british FOC due to expected entry in service of all Block IV modifications, including Meteor and Spear 3) and the budget was much smaller, obviously.
2048 is just the currently envisaged OSD for F-35B (with Typhoon being 2040, you see by yourself how ridiculous that is, but that's how programs begin; it will change later). The MOD has indeed refused to provide estimates for purchases after the first 48, as the first of said purchases is no less than 5 years away and nobody has anything other than a ballpark idea of what the price will be by then.
The MOD written evidence submitted to the Committee for the infamous report that apparently inspired the AvWeek article says nothing about capping purchases; it merely stays (extremely) vague about when they will happen, saying that the "life of the programme" reaches out all the way to 2048 and purchases could continue all along.
Regardless of the vague answers typical of the MOD, any additional purchase is at least 2 reviews and 1 general election away, and sits well outside of the current monetary situation. Saying now that there will be no more purchases is next to pointless as even if it was true it generates exactly 0,0 pounds the government can use. They are not going to decide now, even less they are going to
say it now and take flak they don't need to take.
It only takes logic to see that someone at AvWeek ran a bit too far forward.
At the time the RAF was attributed to say that 63 is the number needed to have 48 available.
Yeah, maybe. But do note: "available" is not even close to "deployable".