Speeds MUCH slower over wifi than ethernet

[#1]

I'm getting speeds of 10 Mbps when plugged in with the ethernet but only speeds of around 1 Mbps when over wifi (even if I am sitting right next to the router with it pointing at me)
Is this just because I have one of the cheap routers that plusnet provide?
Without buying a new router is there any way to improve the wifi speeds?
Thanks for the help

[#2]

The Plusnet routers aren't the best, but they should easily keep up wifi speeds of 20Mbps from close range to even pretty out of date devices..
Probably either a problem with
(1) your device's wifi, or
(2) with the channel you have selected, or
(3) other interference.
To check (1), see if you get any different with other devices.
To check (2), try installing a product like https://www.acrylicwifi.com/en/wlan-software/wlan-scanner-acrylic-wifi-free/ on the device and checking out if there are other channels
(3) is more difficult.  Could be something like a dodgy power supply.  Unplug all power supplies except those you absolutely need to keep things running.

[#3]

I had the same problem until I changed the channel on the router from 11 (which was default) to 6. Then suddenly everything seemed to be okay.
The router I was using at the time was an old Belkin but as sjptd stated, even the old stuff should be able to 'keep up'.
I suppose the only 'scientific' way of testing things is if you have a spare laptop sitting around that you could compare it with.

[#4]

Hi Benmenzies1!
Have you tried the steps outlined at http://www.plus.net/support/broadband/wireless_broadband/wireless_signal.shtml ?

[#5]

As I guess you've realised I am not very knowledgeable about this kind of thing. I have attached a screen shot from me sitting right next to the router (I guess that rules out any question of it being where the router is placed?) so any thoughts would be massively appreciated.
This problem has happened on three different devices I've tried so I don't think it is unique to this laptop?