The Central Athletic Club member, 18, is one of only three Brits to have achieved the 5000m qualifying mark, which he beat by nine seconds.
The delighted former Linlithgow Academy pupil Tweeted: “Buzzing to be called up for my first GB vest for the European U20 Championships in Tallinn. Big thanks to all the guys at @Central_AC and @scotathletics for all the help in my first of hopefully many selections.”
Alastair’s European under-20 race is on July 16 and he travels out to Tallinn on Monday.
His proud dad Stephen, who will also travel out to Estonia with wife Nina to see their boy competing, told the Journal and Gazette: “The qualifying standard for the 5000m is 14 minutes 25 seconds and he ran it in 14 minutes 16 seconds.
"So he’s now among the 27 people who’ll be running in Tallinn.
"I’m very proud of what he’s done. When he was under-13 he was ranked about 800th in the UK and now he’s third.
"Nina and I are going out to watch because we’ve had the two Covid vaccinations. There is a myriad of rules but how often does your son get to run for Great Britain?
"He did the kit drop order the other night and it is masses of stuff so he’s getting quite excited about that.”
Alastair, who has just finished his first year at Stirling University studying a four-year Sports Science course, has previously earned selection for Scotland at youth level.
He has competed in athletics since the age of eight, with Stephen adding: “Alastair was always keen but he’s an example to others about never giving up and being patient while your body develops.
"People would have looked at him when he was aged 10, 11 or 12 and thought: ‘He’ll be a keen club runner’.
"During lockdown he was training hard around Linlithgow. And he brought his 5000m time down by over two minutes.
"He was training with my daughter Katie‘s boyfriend Cameron Harris, who is a Great Britain triathlete. He is a big influence and has been a major factor in my son’s improvement.”