Connectivity issues could be due to many things such as your ISP routing, switching and or browser.
Its well known within the industry that Virgin throttle bandwidth and do traffic shaping . Its not uncommon for Virgin to change routing at specific times of the day and as such you issue could be related to this situation.

In order to be able to progress in resolving this it would be helpful if we knew what OS you are using and what we browser.
The following questions the need to be answered.

1) Do you experience this with any other websites?
2) Do you experience this at specific times or all the time.
3) Are you doing anything else at the time you experience this issue such as downloading.

If you are still experiencing the issue if you provide a trace route it will establish if there is a network latency issue from your location.

A "traceroute" is a function which traces the path from one network to another. It allows us to diagnose the source of many problems. To be effective, the traceroute MUST be run during a time when you are experiencing the problem, from a computer that is experiencing the problem. A trace when you are able to connect, or one from another computer, is not helpful. Therefore, you should try to connect to your site again just before you run it. If the problem is no longer occurring, you will have to wait until the next time the problem occurs (if there is a next time) before running your trace route.

In Windows 2000 or XP, go to "Start" > "Run" and type "cmd" and press the "Enter" key.
This will bring up a 'command prompt" window. It have a line that looks like this:
C:\Documents and Settings\yourname> _
with a cursor blinking next to the ">" symbol.
To run the traceroute type "tracert [hostname]" where the [hostname] is the name of the server that you are connection testing.
This test will proceed some up to a minute or more. It will generate a list of the connection along the way and some information about the speed of the steps along the way. Then you post the complete results (every line) for analysis.
If you have difficulty copying the traceroute information, or if it runs off the screen, you can instead type "tracert yourdomain.name > C:\trace1.txt". This would write the command results to a text file named trace1.txt in the root of your C: drive. You would open this and paste the contents into your response.

Its very difficult for IB to look into something when no information has been provided which can provide information of use, at this time they do no9t know if its an application issue, browser issue, network issue or anything which is within their control.
The manner in which to resolve this would be to ask what information can I provide IB to help them investigate - getting annoyed does not do this