How to prevent R from trying to load mgcv

I need to run 2 different scripts in R without restarting the session. In the first i use the package mgcvand in the second i need gam. I wrote a script which detaches and removes the package mgcv and installs and loads gam. But still after i want to run the gam() function I get an error telling me that mgcv was not found. Which I interpret as R looking for the mgcv package for installing it...

Here's a MWE:

    install.packages(paste(path.pkgs,'mgcv_1.8-7.zip',sep=''),repos=NULL)
    require(mgcv)
    ## FIRST SCRIPT ##

    detach(package:mgcv)
    remove.packages('mgcv')
    unloadNamespace('mgcv')

    require(gam)
    ## SECOND SCRIPT ##
    gam(as.formula(t.thr.fm),data=data)

which returns the error:

   Error in get(method, envir = home) : 
   cannot open file 'H:/data/Documents/R/R-3.1.3/library/mgcv/R/mgcv.rdb': No such file or directory

Any ideas instead of restarting the session?

EDIT:

The solution suggested by Floo0 using package::function is unfortunately not an option.

Solution

you can tell R to take a function from a specific package via this syntax:

package::function

So in your case (do not detach mgtv) and use

mgcv::gam(...)
gam::gam(...)

If the function is not exported in the namespace of the function you can also try package:::function with 3 :