Yes, your old passport will be returned unless it is deemed to be damaged by the UK Identity & Passport Service (IPS). The passport will clearly indicate that it is invalid and it is important that you advise whether any valid visas remain in the passport before applying for it to be renewed.
Hereof, how do you dispose of an old passport?
Make sure you renew your passport before you destroy the old one. It will make the renewal process easier. You might want to keep the old passport as a memento of your travels. If you do dispose of an old passport, shred or burn it, to prevent identity theft.
Do you have to bring your old passport to get a new one?
Here's what you need: Form DS-82, your renewal fee ($110 for an adult), passport photos, and your old passport. Head to a passport agency in person. Lost or stolen passports. If your previous passport was lost or stolen, you'll have to apply for a new one in person.
Do you need to carry old passport?
since travelers travel many countries and they have different type of visas, some post it on passport while other give you a electronic copy like Singapore and that copy will have your passport number. So if those sort of visas are still valid and bearing your old passport number, you must carry both the passports.