A hub, just by the nature of the way it works, is going to be slower than a switch.
Switches are soooooooooooo cheap nowadays that there isnt really a good reason to use a hub.
Hubs send EVERYTHING that comes IN on ANY port back OUT of EVERY port.....so if your comp and another comp are sending info at the same time, they are going to have some data "collisions" happening. If we are on a hub and you and I send at the same time we collide and both comps then have to re-send again...causing a slowdown.
A switch on the other hand doesnt send EVERYTHING out on EVERY port....a switch is smarter and it determines WHERE the packet is being sent bt the MAC address of the destination etc....so if youre comp is sending to the server..then my port of the switch isnt affected at all...cuz the switch knows that I am not the server.
So a switch does basically allow each connection to keep full bandwidth...but with a hub there will be some slowdown.
But like Vass said, it may not really be too noticeable unless there is some serious data moving.
But with 4 or 5 port switches being had for less than $20 bucks now, see if they will buy a switch. I see them often for $10 after rebate..not sure about in the UK though, but still they are super cheap.
JP