Does worsening situation need to be documented?

Hi Chlorinated,
I am sorry ho hear that your condition has deteriorated.
There is no requirement that you have to have a doctor's statement for any award of PIP. However, having a letter from your doctor is more likely for you to get PIP because of course it will help prove your disability.
A lot of PIP awards are based on trust. Whilst x rays and MRI scans can prove someone has arthritis or eg fractured spine, that doesn't necessarily prove the person can not walk 200m without falling or being in serious pain but it will certainly help to prove it. Put the other way, if there is no x Ray or MRI DWP will struggle to understand why someone with no injuries can not walk very far, and will probably award zero points.
If you can't obtain a doctors statement, you can ask for a copy if your medical records which presumably will confirm medical condition and medication. This can help. If not, you can write a statement or get a friend or relative to write one as well. Thete is no reason why you can not perform your own walking test measuring it, or getting a friend to used out the distance You could note when you need to rest, whether you could go out for the same distance the next day etc. You could only make a diary explaining your day to day symptoms and the effect they each have. Your friend could write about the difficulties that they have personally observed.
There is no doubt that a good letter from your GP can be very persuasive, however sometimes a GP can not provide the information required. Many people with long term disability or illness get medication on repeat prescription and don't see the GP. Since Covid actual appointments have decreased too. Also, how does your GP actually know how far you can walk? He may have seen you walk down the corridor, but otherwise he too will rely on the fact that you say you can only walk 100m. Pain is also very subjective too. Many GPS don't know or understand the PIP criteria so can not always supply the correct information. (Remember that things like safety, repetition, speed etc may not be known to the GP , especially for daily living activities.)
But, these situations can be avoided to some extent. If you are claiming PIP or have a review then go and see your GP. It could be a good time to have a medication review. A time to explain your pain memory fatigue etc is worse. Even though you may not need a change of meds, every thing should be recorded and the GPwill be able to write a better letter!
I hope this helps.
LL26

Chlorinated

Just to add.

The distance for the Moving Around activity to be awarded the Enhanced Rate of PIP Mobility, is 20m, not 50m, so if the latter is your current limitation you will not score sufficiently for the higher rate unless you can also score for the Going Out activity!

If you decide to go ahead then look at the information that you can provide.

Give real-world examples of your walking, remember whilst the activity is primarily about the distance other factors, in particular the time it takes need to be taken into account, so measure out a distance you can manage and time yourself, if you need to stop during the walk then the time for this should be included.

Distances need to be repeated, you may not be able to do this immediately and if this is the case then explain why but you should also explain about Post Exertional Malaise and restrictions it might place on you walking the next day.

Be aware of activities you do, for example; shopping. The disabled parking at my local supermarket is probably 40m from the doors and the aisles are at least 30m long. Even if you struggle to walk around the store you are significantly undermining your arguments that your walking is limited.

Gordon