Hi, I am a heavy data user with an unlimited Sim. In the last month I have used 147GB. Tonight my speeds have dropped from a reasonable 4g/5g speed to around 5mbps. I have tested this with numerous devices, checked the coverage checker and service status. Everything appears normal and nothing is showing as having any issues. I am under the impression that ID did not throttle speed after a certain data usage after a reply by an employee here -

“In the UK: Unlimited really means unlimited , no speed caps or data limits for domestic use.”

If there is indeed a throttle after a certain data usage then the reply above is misleading. I have not been abroad or roamed on my sim. 

Can you confirm whether there is a data cap at which point speeds are slowed to an unusable speed? If so, what is that cap? If there is no cap, what is likely to be causing this considering everything appears to be working fine on everything I have checked. 

Many thanks in advance