When the Jubilee is suspended...

The platforms aren't necessarily maintained in a usable state. Stupid, IMHO, but thats what you get for fragmenting the railway, and having excessive layers of red tape.

Any talk about re-opening these platforms for regular use, or do the disadvantages outweigh the benefits?

The current order is that, except in emergencies, Met trains will not call at Neasden or Willesden Green, due to various issues with the platforms there.

Re-opening them for regular use means you slow down the railway between Finchley Road and Wembley, and of course it would have to be decided whether every train will stop or just the local / all-stations trains. Ultimately, the numerous re-timings in order to account for the stops could end up reducing frequencies on certain services.

At Charing Cross the escalators from the Jubilee Line platforms are time-expired and need replacing.

Don't forget that you also have to maintain the platform surface free of weeds, etc.
Then there is the maintenance of the stairs or other access to the platform - at one station (might be Neasden) in the case of emergency detrainment, pax are directed away from the stairs at the souther end of the northbound Met platform, through a subway to the Jubilee platforms, and then all the way along the platforms to the stairs at the southern end.

Why is this?

When I was over there, the platforms looked in a good state with lighting working and even OPO screens operational ! I can see no reason why they can not be used

Exactly how much paperwork is required to permit trains to stop at a platform which is in a fit state ?

As for staffing, at the times when trains are stopping, extra staff could be brought in (if it were done at times when the Jubilee were suspended, surely they could be staff who would normally work at those Jubilee stations which are closed?).

This whole thread appears to have passed from the reality - i.e. Met trains do not stop at Neasden and Willesden - to one of those wild idea threads.

Neasden and Willesden are managed by the Jubilee Line. As such they require Jubilee Line staff to man them. Alongside this, it requires Tubelines and the Jubilee Line management to sign off all the paperwork. On top of this requirement, there also has to be agreement reached between the Jubilee, Tubelines and the Metropolitan line management on how frequently trains will stop. For example, will everything be signed off for emergency evacuation only (which has been done) or will it all be signed off for all-day / everyday use (which it hasn't).

Once all the paperwork has been done, and once you get everything to a point where you have specified how many staff you need to oversee operation of both stations (bearing in mind there will be 2 separate lines stopping there) you then have to work out how to pay for, and supply the staff.

The Jubilee Line already has it's own line which runs parallel to the Met as far as these stations are concerned. In the current economic climate, would there really be any firm justification to pay out wads of cash to allow the Met line to stop at the 2 stations.

On top of this, as I touched on earlier, what advantage would the Met receive in stopping trains at these stations? Overall slower journey times, and maybe even a decrease in northbound frequencies, which would not go down well with many users of the Met Line.

So whilst I can see the OP's point that it would be handy to be able to utilise these stations during service suspensions, unfortunately it's one of those cases where the cost and paperwork simply does not justify opening on the odd weekend now and again.

Other than this, is there any real benefit to anybody in having duplicate services, both running pretty slowly between Finchley Road and Wembley Park, with no real interchange opportunity (other than between each other).

When S stock arrives and the driver and PEA-operator are able to communicate, and the nature of the emergency means that a quick stop is called for, will this come under the emergency use arrangements for use of these platforms?

I read that after I replied to the post above you, so hopefully that answers your query ;D

Just to add, can you imagine the chaos and accidents when a Met is spotted approaching at either station? You only have to look at Wembley during the off-peak to spot the maniacs running across the bridge to platform 6.