Drive along gently and with window open, pull the handbrake on a bit. If you hear the same scraping, it is the rear shoes worn past limits. Pick some up from eBay or Motor factors.
If no noise from rear or handbrake and you still get the noise with footbrake, get some front pads as above. If you have a pad wear light on the dash .. and it's flashing, make sure pads are with wear sensor wires. 1990 Escort is a Mk4 or early Mk5. Check this first.
Providing it's not an XR3/i or turbo, pads will be about £10 (or £15 wired) Shoes will be about £15, shoes vary according to engine size or XR/i/Turbo too.