No Bathroom at Buckingham?

I, personally, would use the free bathrooms at Victoria Railway Station- which is about a ten minute walk round from where the tour starts.
But I agree that, given the price of the tour, it is a bit much that they can't provide facilities at the start of the tour.

That is also what the tour page says. However looking it up there are also bathrooms a bit closer at the Playground in St James' Park, off Birdcage Walk, opposite West Island.
I didn't know they were there, so can't vouch for them but they are supposed to be open 10.00 - 16.00 January, November & December.,10.00 - 17.00 February., 10.00 - 18.00 March & October., 10.00 - 19.00 September., 10.00 - 19.30 April, May, June, July & August. The cost is 20p- contactless payments only.

If you use google maps for hotels and restaurants, you will find several a bit nearer than the station, who will probable ley you use the facilities for the price of a coffee.

Confirming St James Park has toilets - the ones I'm aware off are where Marlborough Road meets The Mall, so not far, depending which direction you're coming from. Not sure about the playground ones, but those would be closer. And there are plenty of cafes etc in St James' and Victoria.

Yes, the toilet facilities at the palace are in a temporary structure in the gardens, near the cafe, so at the end of the tour.

Under the accessibility section there is mention of one toilet at the beginning of the accessible route but this is a different entrance that requires prior arrangement to use I guess because it is low capacity.

Toilet map (www.toiletmap.org.uk) shows the public ones already mentioned plus a couple of others fairly nearby.

This won’t help the situation of anyone visiting there, but you’d think a royal palace would have a few more thrones. ;)

I've updated toilet.map (above) this morning (as I did when Mardee was going to Tower Hill the other week) with up to date information about the charges for the St James' Park toilets.

If my memory is correct from my Oct. trip, the St. James’ Park playground toilets are for kids only. Those are closest to the palace. The ones that adults can use are a little further away from the palace.

EDIT: I see from the map Marco provided above that the St. James’ Park playground toilets are indeed for kids only. So, don’t plan on using those.

The situation in St James' Park is very confusing. The underlying Royal Parks Map does not show the Playground toilets as existing any longer, however they list opening hours for them (for everyone to use). However the Royal Parks Map does show toilets up near The Guards memorial but does not give opening times for them. Something is clearly amiss.
There is a note now on the system that the situation in the whole park needs verifying.

You would be justified in requesting use of the accessible entrance as your need for a toilet is an accessibility issue.

Do you plan to go visit the King's Gallery which is just a few steps away from the Buckingham Palace public entrance? They have wonderful toilettes BUT they are inside the ticket and security barriers so you'd need to have entries there.

I can confirm that there are no bathrooms for the Buckingham Palace tour until the very end, when you exit out to the garden. There, they have port-a-potty toilets. If you are looking for a toilet to use before the tour, a short walk from Buckingham Palace is Gail’s Bakery, which should have toilets. If you are feeling brave, there is a hotel called The Resident Victoria (I have stayed there twice), right near the Buckingham Palace gift shop. Pop into the hotel, walk past the reception desk, and find the bathroom on the left.

Could you not just have a bath in your hotel before breakfast.

"Could you not just have a bath in your hotel before breakfast."

Hilarious.."two countries separated by a common language"...