I and no doubt many others keep getting mixed up as to which Foggy Dew we are talking about. There is a delightful English song about seduction and the perils of sleeping in the open in a damp English climate. The other is a sombre Irish song called The Foggy Dew dealing with the Easter Rebellion in Dublin and the perils of "... Britannia's sons with their long-range guns".
I grew up with "The Foggy, Foggy Dew" and no longer know where I first heard and learned it.
The version I sing these days (1999) can be found in Songs and Dances of England by Liz Thomson. This version is too short and too "nice" for my taste and I have a gut-feeling that there must be a lot, lot more and a little less sanitised out there somewhere. I would be delighted to learn of other verses.

Since writing the above in 1999, surfer Andrew Dalby sent me a fantastic Norfolk very human version in March, 2006, which entirely met and exceeded my expectations. Thanks a million Andrew!

Lyrics transcribed by Andrew Dalby from a 40-year old recording The folk songs of England

O I am a bachelor an I live alone
An I work in the weaver's trade;
An the only, only thing that I ever done wrong
Was courtin a fair young maid.
I courted her one summertime,
An all the winter too,
An the only, only thing that I never should ha done
Was to save her from the foggy, foggy dew.

I got that tired a livin alone
I says to her one day:
'I've a nice little crib in my old shack
Where you might safely lay.
You'll be all right in the summertime
An in the winter too:
You'll lay right warm an take no harm
Away from the foggy, foggy dew.'

One night she come to my bed side
Time I lay fast asleep.
She puts her head down on my bed
An she starts in to weep;
She yelled and cried, she well near died,
She say: 'What shall I do?'
So I haul her into bed an I covered up her head
To save her from the foggy, foggy dew.

Says I, 'My dear, lay close to me
An wipe away them tears.'
Then I hauled her shift up over her head
An I wrapped it round her ears.
We was all right in the wintertime
An in the summer too,
An I held her tight that livelong night
To save her from the foggy, foggy dew.

'Now lay you still, you silly young fool,
An don't you feel afraid,
For if you want to work with me
You got to learn yer trade.'
I learned her all that summertime
An all the winter too,
An, truth to tell, she learned that well
She saved us from the foggy foggy dew.

One night I lay there good as gold
An then she say to me:
'I got a pain athwart my back
Where no pain ought to be.
I was all right in the summertime
An in the winter too,
But I've took some ill or a kind of a chill
From layin in the foggy, foggy dew.'

One night she start to moan and cry.
Says I, 'What's up wi you?'
She say: 'I never should ha bin this way
If that hanna bin for you.'
I got my boots and trousers on,
I got my neighbour too,
But do what we would we couldn do no good
An she died in the foggy, foggy dew.

So I am a bachelor, I live wi my son
An we work in the weavin trade.
And every time I look in his face I can see
The eyes o that fair young maid.
That remind me of the summertime
An of the winter, too,
An the many, many times she lay in my arms
To save her from the foggy, foggy dew.