If youâ€™ve tried to order lateral flow tests online in recent days, youâ€™ve probably encountered the message: â€œSorry, there are no more home delivery slots for these tests right now.â€ Unless, that is, youâ€™re Dave McNally or one of his 16.3k Twitter followers.
In late December, he wrote a software application that would rapidly fill out the form to the point where it became clear if any tests were in stock â€“ and then share that information via the Twitter account UK @LFT_alert.
The insights he has gained shed new light on why so many people have been struggling to order tests: batches are released only a couple of times a day, at specific (and unadvertised) times, and stock is often exhausted within the hour.
With the government announcing the end of free Covid testing for most people in England on Friday, the demand for LFTs (lateral flow tests) means they are increasingly snapped up within minutes of becoming available.
â€œOn Monday evening, it was only 45 minutes, and there was an afternoon session of 18 minutes â€“ so, only an hour and three minutes in total,â€ said McNally. â€œPeople are going to be wasting their time on the site trying to order the damned things if they donâ€™t know the time slot.
â€œThatâ€™s why Iâ€™ve made a point of posting quite regularly: â€˜itâ€™s always 8 oâ€™clock pm. Tell people, because not everyoneâ€™s on Twitterâ€™.â€
He added: â€œI think demand has really picked up this week. I wouldnâ€™t be surprised if on Thursday we see a five-minute window or something stupid like that.â€
McNally, 46, from Bristol, started the project after struggling to get hold of any LFTs due to high demand post-Christmas. As a web developer and self-confessed â€œdata-nerdâ€, it was relatively easy for him to write a program to automate the form-filling process, allowing him to get hold of tests as soon as they were back in stock.
The next day, he noticed someone on Twitter complaining of exactly the same problem: â€œI thought, itâ€™s a bit selfish to have just done this for myself, when thereâ€™s probably thousands of people having exactly the same difficulties, and I could just create a Twitterbot [to share that information],â€ McNally said.
Launched on 31 December, the bot rapidly accumulated a loyal fanbase, as people shared and retweeted its vital information.
According to McNallyâ€™s data, those initial problems with LFT supply ended on 10 January. But then in early March, people started messaging him to say they were once again struggling to access tests. McNally discovered the bot had stopped working, but it was back up and running by 13 March. â€œIn came the stock at 8pm, and lasted 2.5 hours. Ever since then, itâ€™s been 8pm each day, plus sometimes 7am, sometimes 12pm, sometimes 2pm â€“ but always 8pm,â€ he said.
There are regional differences: Scotland started running out of tests only during the past week â€“ but their window of availability appears to be growing shorter each day. Wales and Northern Ireland always seem to have plenty of tests available, McNally said.
He has received a lot of grateful messages on Twitter, â€œwhich is lovelyâ€, but he has also been alarmed by some of the comments â€“ particularly from health professionals, saying theyâ€™ve also struggled to get hold of tests. â€œIf youâ€™re working the same shifts every day, you canâ€™t necessarily get online to get an 8pm slot. Thatâ€™s kind of scary,â€ he said. â€œIf youâ€™re trying at certain times of day, youâ€™ll never get any.â€