Jazz Carlin has admitted she was haunted by past failure after she failed to make the Olympic qualifying time, despite winning gold at the British Swimming Championships in Glasgow on Friday night.

The Wales Commonwealth Games champion touched first in the 800m freestyle but was well outside the time she needed for automatic selection for Rio de Janerio.

Carlin will now have to wait to see if she gets picked by the Great Britain selectors – a decent bet since the 25-year-old’s time of at 08:27.49 falls within the 2 per cent consideration standard of the Olympic benchmark of 08:22.93.

The winning time was well behind her efforts of last year when she won in a time of 8:21.58. Carlin also posted a swift 8:18.15 to earn the bronze medal in the event at the 2015 FINA World Championships.

But the Swansea-based swimmer admitted she was affected by anxiety after missing out on selection for the London Olympics in 2012.

She said: “Missing out on London four years ago means it’s a bit like ghosts from the past. It dawned on me this week and it felt like everything is now closing in on me.

“It’s something I have been trying to work on to try stay relaxed, but and it’s something that gets to everyone. There is a lot of pressure for everyone and a lot of nerves. I have just got to try and keep my head up for the rest of the week.

“It has been a bit of a tussle for a couple of weeks. I have really put a lot of pressure on myself to not miss out on the Olympics, four years ago it was heart-breaking for me.

“It has been tough and I just didn’t feel myself, when you are racing tense you start to get a bit heavy.”

Carlin will now race again in the 400m on Saturday and hope to avoid another disappointing time. Just four swimmers have logged British Olympic-qualifying standards over the first three days of competition.

She added: “It’s always good to race the best in Britain. I now have a day off, so I will put my feet up and chill out. Then, I’ll come back fighting on Saturday.”