Royal Mail delivers post and parcels to more than 32 million addresses across the UK.
The postal services website says it delivers and collects mail on "most days".
If you are waiting for a letter or a parcel, and it hasn't arrived during the week, you may be wondering if there is a chance of it arriving on the weekend.
Most Harry Potter fans will know, there is no post on Sundays, but what about Saturdays?
Does Royal Mail deliver on Saturdays?
Currently (at the time of publication) yes, Royal Mail does deliver post and parcels on Saturdays.
The Royal Mail’s universal service obligation (USO) forces it to deliver letters six days a week to all 32 million addresses in the UK for the price of a stamp, no matter where the letters are going.
The Royal website says: "We deliver and collect your mail on most days of the year, including Saturdays."
It did however outline the days it doesn't deliver.
Royal Mail added: "However, we don’t usually deliver or collect on public or local holidays."
You can see all the holidays Royal Mail doesn't deliver on its website here.
There is also, in the words of Vernon Dursley in Harry Potter and the Philosopher's Stone, "no post on Sundays" in some cases.
However, Royal Mail will deliver parcels on Sundays and letters/post if senders have purchased 'Special Delivery Guaranteed'.
Royal Mail explained: "Where Special Delivery Guaranteed has been purchased, both letters and parcels will be delivered on a Sunday.
"For Tracked items, we are focussing on parcels only for Sunday delivery."
For more information on Royal Mail delivery services, visit its website.
Royal Mail looking to scrap Saturday deliveries
While Royal Mail currently delivers six days a week, including Saturdays, its owner International Distributions Services (IDS) has formally asked the Government to switch to a five-days-a-week letter delivery service which would cover Monday to Friday.
While the proposal would see a five-day letter delivery system the group said it would look to maintain a seven-day parcel delivery service.
Royal Mail has urged the Government and Ofcom to review its obligations, given the decline in addressed letter post.
Why is Black Friday called Black Friday?
Regulator Ofcom is due to report back this week on its review of the universal service provided by Royal Mail after the proposal to ditch Saturday letter deliveries.
Downing Street said the Government would not support any plans enabling Royal Mail to ditch its six-day-a-week letter postal service.
The Prime Minister, Rishi Sunak's official spokesman said: “The Prime Minister’s strong view is that Saturday deliveries provide flexibility and convenience that are important for businesses and particularly publishers and the Prime Minister would not countenance seeing Saturday deliveries scrapped."
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