If I caught covid on Saturday or Sunday when will an LFT show positive?

[Digforbritain]

Travelled to London by train on Saturday/ Sunday. Used the tube, went to the theatre, restaurants shops etc.

Had a headache last night and this evening feel a little snotty and tired. Very faint sore throat.

LFT negative, if it’s covid when will it show on LFT after exposure?

Most of my friends and relatives who have caught Covid, never once tested positive on an LFT. Only PCRs.

DS - 5th LFT (so 5th day), PCR positive on Day 2.

Meant to add it took 5 days to get PCR result hence so many tests!

Incubation of delta was 6-10 days from exposure. Omicron is thought to be 5-7 from what I’ve read.

Track and trace told us day 5 was the average, but I’m not sure if that was on LFT or PCR. DH was the first to get covid dec 2020, he isolated in our bedroom, I left food outside on a tray. The day me and the 3 docs were allowed out from isolation, I started coughing, and had a positive PCR two days later, so 13 days after I’d spent any proper time with DH.
I dare say with the variants it’s all changed now though. Hope you stay well.

SIL was exposed on Sunday afternoon (confirmed), had symptoms on Tuesday lunchtime & positive LFT that evening. LFTs were negative on Monday & Tuesday morning so about 55 hours for the positive. DB was exposed at exactly the same time & didn't catch it (LFTs & PCR negative).